Contextual effects on smooth-pursuit eye movements.

Science.gov (United States)

Spering, Miriam; Gegenfurtner, Karl R

2007-02-01

Segregating a moving object from its visual context is particularly relevant for the control of smooth-pursuit eye movements. We examined the interaction between a moving object and a stationary or moving visual context to determine the role of the context motion signal in driving pursuit. Eye movements were recorded from human observers to a medium-contrast Gaussian dot that moved horizontally at constant velocity. A peripheral context consisted of two vertically oriented sinusoidal gratings, one above and one below the stimulus trajectory, that were either stationary or drifted into the same or opposite direction as that of the target at different velocities. We found that a stationary context impaired pursuit acceleration and velocity and prolonged pursuit latency. A drifting context enhanced pursuit performance, irrespective of its motion direction. This effect was modulated by context contrast and orientation. When a context was briefly perturbed to move faster or slower eye velocity changed accordingly, but only when the context was drifting along with the target. Perturbing a context into the direction orthogonal to target motion evoked a deviation of the eye opposite to the perturbation direction. We therefore provide evidence for the use of absolute and relative motion cues, or motion assimilation and motion contrast, for the control of smooth-pursuit eye movements.

Doing smooth pursuit paradigms in Windows 7

DEFF Research Database (Denmark)

Wilms, Inge Linda

predict strengths or deficits in perception and attention. However, smooth pursuit movements have been difficult to study and very little normative data is available for smooth pursuit performance in children and adults. This poster describes the challenges in setting up a smooth pursuit paradigm...... in Windows 7 with live capturing of eye movements using a Tobii TX300 eye tracker. In particular, the poster describes the challenges and limitations created by the hardware and the software...

Efference copy failure during smooth pursuit eye movements in schizophrenia.

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Spering, Miriam; Dias, Elisa C; Sanchez, Jamie L; Schütz, Alexander C; Javitt, Daniel C

2013-07-17

Abnormal smooth pursuit eye movements in patients with schizophrenia are often considered a consequence of impaired motion perception. Here we used a novel motion prediction task to assess the effects of abnormal pursuit on perception in human patients. Schizophrenia patients (n = 15) and healthy controls (n = 16) judged whether a briefly presented moving target ("ball") would hit/miss a stationary vertical line segment ("goal"). To relate prediction performance and pursuit directly, we manipulated eye movements: in half of the trials, observers smoothly tracked the ball; in the other half, they fixated on the goal. Strict quality criteria ensured that pursuit was initiated and that fixation was maintained. Controls were significantly better in trajectory prediction during pursuit than during fixation, their performance increased with presentation duration, and their pursuit gain and perceptual judgments were correlated. Such perceptual benefits during pursuit may be due to the use of extraretinal motion information estimated from an efference copy signal. With an overall lower performance in pursuit and perception, patients showed no such pursuit advantage and no correlation between pursuit gain and perception. Although patients' pursuit showed normal improvement with longer duration, their prediction performance failed to benefit from duration increases. This dissociation indicates relatively intact early visual motion processing, but a failure to use efference copy information. Impaired efference function in the sensory system may represent a general deficit in schizophrenia and thus contribute to symptoms and functional outcome impairments associated with the disorder.

Nearly Cyclic Pursuit and its Hierarchical variant for Multi-agent Systems

DEFF Research Database (Denmark)

Iqbal, Muhammad; Leth, John-Josef; Ngo, Trung Dung

2015-01-01

The rendezvous problem for multiple agents under nearly cyclic pursuit and hierarchical nearly cyclic pursuit is discussed in this paper. The control law designed under nearly cyclic pursuit strategy enables the agents to converge at a point dictated by a beacon. A hierarchical version of the nea......The rendezvous problem for multiple agents under nearly cyclic pursuit and hierarchical nearly cyclic pursuit is discussed in this paper. The control law designed under nearly cyclic pursuit strategy enables the agents to converge at a point dictated by a beacon. A hierarchical version...

Temporal dynamics of retinal and extraretinal signals in the FEFsem during smooth pursuit eye movements.

Science.gov (United States)

Bakst, Leah; Fleuriet, Jérome; Mustari, Michael J

2017-05-01

Neurons in the smooth eye movement subregion of the frontal eye field (FEFsem) are known to play an important role in voluntary smooth pursuit eye movements. Underlying this function are projections to parietal and prefrontal visual association areas and subcortical structures, all known to play vital but differing roles in the execution of smooth pursuit. Additionally, the FEFsem has been shown to carry a diverse array of signals (e.g., eye velocity, acceleration, gain control). We hypothesized that distinct subpopulations of FEFsem neurons subserve these diverse functions and projections, and that the relative weights of retinal and extraretinal signals could form the basis for categorization of units. To investigate this, we used a step-ramp tracking task with a target blink to determine the relative contributions of retinal and extraretinal signals in individual FEFsem neurons throughout pursuit. We found that the contributions of retinal and extraretinal signals to neuronal activity and behavior change throughout the time course of pursuit. A clustering algorithm revealed three distinct neuronal subpopulations: cluster 1 was defined by a higher sensitivity to eye velocity, acceleration, and retinal image motion; cluster 2 had greater activity during blinks; and cluster 3 had significantly greater eye position sensitivity. We also performed a comparison with a sample of medial superior temporal neurons to assess similarities and differences between the two areas. Our results indicate the utility of simple tests such as the target blink for parsing the complex and multifaceted roles of cortical areas in behavior. NEW & NOTEWORTHY The frontal eye field (FEF) is known to play a critical role in volitional smooth pursuit, carrying a variety of signals that are distributed throughout the brain. This study used a novel application of a target blink task during step ramp tracking to determine, in combination with a clustering algorithm, the relative contributions of

Smooth pursuit adaptation (SPA exhibits features useful to compensate changes in the properties of the smooth pursuit eye movement system due to usage.

Directory of Open Access Journals (Sweden)

Suryadeep eDash

2013-10-01

Full Text Available Smooth-pursuit adaptation (SPA refers to the fact that pursuit gain in the early, still open-loop response phase of the pursuit eye movement can be adjusted based on experience. For instance, if the target moves initially at a constant velocity for approximately 100-200ms and then steps to a higher velocity, subjects learn to up-regulate the pursuit gain associated with the initial target velocity (gain-increase SPA in order to reduce the retinal error resulting from the velocity step. Correspondingly, a step to a lower target velocity leads to a decrease in gain (gain-decrease SPA. In this study we demonstrate that the increase in peak eye velocity during gain-increase SPA is a consequence of expanding the duration of the eye acceleration profile while the decrease in peak velocity during gain-decrease SPA results from reduced peak eye acceleration but unaltered duration. Furthermore, we show that carrying out stereotypical smooth pursuit eye movements elicited by constant velocity target ramps for several hundred trials (= test of pursuit resilience leads to a clear drop in initial peak acceleration, a reflection of oculomotor and/ or cognitive fatigue. However, this drop in acceleration gets compensated by an increase in the duration of the acceleration profile, thereby keeping initial pursuit gain constant. The compensatory expansion of the acceleration profile in the pursuit resilience experiment is reminiscent of the one leading to gain-increase SPA, suggesting that both processes tap one and the same neuronal mechanism warranting a precise acceleration/ duration trade-off. Finally, we show that the ability to adjust acceleration duration during pursuit resilience depends on the integrity of the oculomotor vermis (OMV as indicated by the complete loss of the duration adjustment following a surgical lesion of the OMV in one rhesus monkey we could study.

Effects of contrast on smooth pursuit eye movements.

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Spering, Miriam; Kerzel, Dirk; Braun, Doris I; Hawken, Michael J; Gegenfurtner, Karl R

2005-05-20

It is well known that moving stimuli can appear to move more slowly when contrast is reduced (P. Thompson, 1982). Here we address the question whether changes in stimulus contrast also affect smooth pursuit eye movements. Subjects were asked to smoothly track a moving Gabor patch. Targets varied in velocity (1, 8, and 15 deg/s), spatial frequency (0.1, 1, 4, and 8 c/deg), and contrast, ranging from just below individual thresholds to maximum contrast. Results show that smooth pursuit eye velocity gain rose significantly with increasing contrast. Below a contrast level of two to three times threshold, pursuit gain, acceleration, latency, and positional accuracy were severely impaired. Therefore, the smooth pursuit motor response shows the same kind of slowing at low contrast that was demonstrated in previous studies on perception.

Discrimination of curvature from motion during smooth pursuit eye movements and fixation.

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Ross, Nicholas M; Goettker, Alexander; Schütz, Alexander C; Braun, Doris I; Gegenfurtner, Karl R

2017-09-01

Smooth pursuit and motion perception have mainly been investigated with stimuli moving along linear trajectories. Here we studied the quality of pursuit movements to curved motion trajectories in human observers and examined whether the pursuit responses would be sensitive enough to discriminate various degrees of curvature. In a two-interval forced-choice task subjects pursued a Gaussian blob moving along a curved trajectory and then indicated in which interval the curve was flatter. We also measured discrimination thresholds for the same curvatures during fixation. Motion curvature had some specific effects on smooth pursuit properties: trajectories with larger amounts of curvature elicited lower open-loop acceleration, lower pursuit gain, and larger catch-up saccades compared with less curved trajectories. Initially, target motion curvatures were underestimated; however, ∼300 ms after pursuit onset pursuit responses closely matched the actual curved trajectory. We calculated perceptual thresholds for curvature discrimination, which were on the order of 1.5 degrees of visual angle (°) for a 7.9° curvature standard. Oculometric sensitivity to curvature discrimination based on the whole pursuit trajectory was quite similar to perceptual performance. Oculometric thresholds based on smaller time windows were higher. Thus smooth pursuit can quite accurately follow moving targets with curved trajectories, but temporal integration over longer periods is necessary to reach perceptual thresholds for curvature discrimination. NEW & NOTEWORTHY Even though motion trajectories in the real world are frequently curved, most studies of smooth pursuit and motion perception have investigated linear motion. We show that pursuit initially underestimates the curvature of target motion and is able to reproduce the target curvature ∼300 ms after pursuit onset. Temporal integration of target motion over longer periods is necessary for pursuit to reach the level of precision found

Application of Boosting Regression Trees to Preliminary Cost Estimation in Building Construction Projects

Directory of Open Access Journals (Sweden)

Yoonseok Shin

2015-01-01

Full Text Available Among the recent data mining techniques available, the boosting approach has attracted a great deal of attention because of its effective learning algorithm and strong boundaries in terms of its generalization performance. However, the boosting approach has yet to be used in regression problems within the construction domain, including cost estimations, but has been actively utilized in other domains. Therefore, a boosting regression tree (BRT is applied to cost estimations at the early stage of a construction project to examine the applicability of the boosting approach to a regression problem within the construction domain. To evaluate the performance of the BRT model, its performance was compared with that of a neural network (NN model, which has been proven to have a high performance in cost estimation domains. The BRT model has shown results similar to those of NN model using 234 actual cost datasets of a building construction project. In addition, the BRT model can provide additional information such as the importance plot and structure model, which can support estimators in comprehending the decision making process. Consequently, the boosting approach has potential applicability in preliminary cost estimations in a building construction project.

Smooth Pursuit Saccade Amplitude Modulation During Exposure to Microgravity

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Reschke, M. F.; Kozlovskaya, I. B.; Sayenko, D. G.; Sayenko, I.; Somers, J. T.; Paloski, W. H.

2002-01-01

Russian investigators have reported changes in pursuit tracking of a vertically moving point stimulus during space flight. Early in microgravity, changes were manifested by decreased eye movement amplitude (undershooting) and the appearance of correction saccades. As the flight progressed, pursuit of the moving point stimulus deteriorated while associated saccadic movements were unchanged. Immediately postflight there was an improved execution of active head movements indicating that the deficiencies in pursuit function noted in microgravity may be of central origin. In contrast, tests of two cosmonauts showed that horizontal and vertical smooth pursuit were unchanged inflight. However, results of corresponding saccadic tasks showed a tendency toward the overshooting of a horizontal target early inflight with high accuracy developing later inflight, accompanied by an increased saccade velocity and a trend toward decreased saccade latency. Based on these equivocal results, we have further investigated the effects of space flight on the smooth pursuit mechanism during and after short duration flight, and postflight on returning MIR crewmembers. Sinusoidal target movement was presented horizontally at frequencies of 0.33 and 1.0 Hz. Subjects were asked to perform two trials for each stimulus combination: (1) moving eyes-only (EO) and (2) moving eyes and head (EH) with the target motion. Peak amplitude was 30 deg for 0.33 Hz trials and 15 deg for the 1.0 Hz trials. The relationship between saccade amplitude and peak velocity were plotted as a main sequence for each phase of flight, and linear regression analysis allowed us to determine the slope of each main sequence plot. The linear slopes were then combined for each flight phase for each individual subject. The main sequence for both EO and EH trials at both the 0.33 and 1.0 Hz frequencies during flight for the short duration flyers showed a reduction in saccade velocity and amplitude when compared to the preflight

Multiagent pursuit-evasion games: Algorithms and experiments

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Kim, Hyounjin

Deployment of intelligent agents has been made possible through advances in control software, microprocessors, sensor/actuator technology, communication technology, and artificial intelligence. Intelligent agents now play important roles in many applications where human operation is too dangerous or inefficient. There is little doubt that the world of the future will be filled with intelligent robotic agents employed to autonomously perform tasks, or embedded in systems all around us, extending our capabilities to perceive, reason and act, and replacing human efforts. There are numerous real-world applications in which a single autonomous agent is not suitable and multiple agents are required. However, after years of active research in multi-agent systems, current technology is still far from achieving many of these real-world applications. Here, we consider the problem of deploying a team of unmanned ground vehicles (UGV) and unmanned aerial vehicles (UAV) to pursue a second team of UGV evaders while concurrently building a map in an unknown environment. This pursuit-evasion game encompasses many of the challenging issues that arise in operations using intelligent multi-agent systems. We cast the problem in a probabilistic game theoretic framework and consider two computationally feasible pursuit policies: greedy and global-max. We also formulate this probabilistic pursuit-evasion game as a partially observable Markov decision process and employ a policy search algorithm to obtain a good pursuit policy from a restricted class of policies. The estimated value of this policy is guaranteed to be uniformly close to the optimal value in the given policy class under mild conditions. To implement this scenario on real UAVs and UGVs, we propose a distributed hierarchical hybrid system architecture which emphasizes the autonomy of each agent yet allows for coordinated team efforts. We then describe our implementation on a fleet of UGVs and UAVs, detailing components such

Assessment of working women's perception and pursuit of recreation

African Journals Online (AJOL)

Assessment of working women's perception and pursuit of recreation. ... Africa, to participate in two focus group interviews at the workplace of the respondents. ... Three underlying themes, namely barriers, benefits, and attitude and pursuits ...

Neurophysiology and Neuroanatomy of Smooth Pursuit: Lesion Studies

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Sharpe, James A.

2008-01-01

Smooth pursuit impairment is recognized clinically by the presence of saccadic tracking of a small object and quantified by reduction in pursuit gain, the ratio of smooth eye movement velocity to the velocity of a foveal target. Correlation of the site of brain lesions, identified by imaging or neuropathological examination, with defective smooth…

Evidence for object permanence in the smooth-pursuit eye movements of monkeys.

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Churchland, Mark M; Chou, I-Han; Lisberger, Stephen G

2003-10-01

We recorded the smooth-pursuit eye movements of monkeys in response to targets that were extinguished (blinked) for 200 ms in mid-trajectory. Eye velocity declined considerably during the target blinks, even when the blinks were completely predictable in time and space. Eye velocity declined whether blinks were presented during steady-state pursuit of a constant-velocity target, during initiation of pursuit before target velocity was reached, or during eye accelerations induced by a change in target velocity. When a physical occluder covered the trajectory of the target during blinks, creating the impression that the target moved behind it, the decline in eye velocity was reduced or abolished. If the target was occluded once the eye had reached target velocity, pursuit was only slightly poorer than normal, uninterrupted pursuit. In contrast, if the target was occluded during the initiation of pursuit, while the eye was accelerating toward target velocity, pursuit during occlusion was very different from normal pursuit. Eye velocity remained relatively stable during target occlusion, showing much less acceleration than normal pursuit and much less of a decline than was produced by a target blink. Anticipatory or predictive eye acceleration was typically observed just prior to the reappearance of the target. Computer simulations show that these results are best understood by assuming that a mechanism of eye-velocity memory remains engaged during target occlusion but is disengaged during target blinks.

Are altered smooth pursuit eye movements related to chronic pain and disability following whiplash injuries? A prospective trial with one-year follow-up.

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Kongsted, Alice; Jørgensen, Lars Vincents; Leboeuf-Yde, Charlotte; Qerama, Erisela; Korsholm, Lars; Bendix, Tom

2008-05-01

To evaluate the ability of early smooth pursuit testing to predict chronic whiplash-associated disorders, and to study whether the presence of abnormal smooth pursuit eye movements at one-year follow-up is associated with symptoms at that time. Prospective cohort study with one-year follow-up. The study was carried out at a university research centre and participants were recruited from emergency units and general practitioners. In all, 262 participants were recruited within 10 days from a whiplash injury. Smooth pursuit eye movements were tested with electrooculography (EOG) an average of 12 days after a whiplash trauma and again after one year. Analyses of EOG recordings were computerized. Associations between test results both from baseline and one-year tests and self-reported neck pain, headache, neck disability and working ability one year after the car collision were determined. Results of early eye movement tests were not associated with the prognosis. Reduced smooth pursuit performance when tested in static cervical rotation at the one-year follow-up was significantly associated with higher neck pain intensity at that time (regression coefficient 0.8, 95% confidence interval (CI) 0.04-1.5), but the association was too weak for the test to discriminate between recovered participants and those with lasting symptoms. Although reduced smooth pursuit performance at one-year follow-up was associated with persistent neck pain, smooth pursuit eye movement tests are not useful as predictive or diagnostic tests in whiplash-associated disorders.

FEFsem neuronal response during combined volitional and reflexive pursuit.

Science.gov (United States)

Bakst, Leah; Fleuriet, Jérome; Mustari, Michael J

2017-05-01

Although much is known about volitional and reflexive smooth eye movements individually, much less is known about how they are coordinated. It is hypothesized that separate cortico-ponto-cerebellar loops subserve these different types of smooth eye movements. Specifically, the MT-MST-DLPN pathway is thought to be critical for ocular following eye movements, whereas the FEF-NRTP pathway is understood to be vital for volitional smooth pursuit. However, the role that these loops play in combined volitional and reflexive behavior is unknown. We used a large, textured background moving in conjunction with a small target spot to investigate the eye movements evoked by a combined volitional and reflexive pursuit task. We also assessed the activity of neurons in the smooth eye movement subregion of the frontal eye field (FEFsem). We hypothesized that the pursuit system would show less contribution from the volitional pathway in this task, owing to the increased involvement of the reflexive pathway. In accordance with this hypothesis, a majority of FEFsem neurons (63%) were less active during pursuit maintenance in a combined volitional and reflexive pursuit task than during purely volitional pursuit. Interestingly and surprisingly, the neuronal response to the addition of the large-field motion was highly correlated with the neuronal response to a target blink. This suggests that FEFsem neuronal responses to these different perturbations-whether the addition or subtraction of retinal input-may be related. We conjecture that these findings are due to changing weights of both the volitional and reflexive pathways, as well as retinal and extraretinal signals.

The sweetness of successful goal pursuit: Approach-motivated pregoal states enhance the reward positivity during goal pursuit.

Science.gov (United States)

Threadgill, A Hunter; Gable, Philip A

2017-12-21

Traditionally, the reward positivity (RewP) is thought to index a binary performance monitoring system sensitive to approach motivation. However, recent theoretical models have argued that feedback processing extends beyond simple "good" vs. "bad" associations, such that performance monitoring incorporates the complex, multi-step sequence of behaviors often necessary to attain rewards. The present study sought to go beyond simple stimulus-response paradigms to examine how approach-motivated states occurring in multi-step goal pursuit impacts the RewP. Additionally, outcome frequency was varied to examine how the P3, a neural marker of expectancy, influences the RewP. Using a modified monetary incentive delay paradigm, participants played a reaction time game where multiple correct responses were required to attain a reward. Additionally, each trial had the potential for a reward (approach-motivated state) or no reward (neutral state). Results revealed that RewP amplitudes were larger after reward trial win feedback than after reward trial no-win feedback across multiple stages of goal pursuit. Additionally, after for controlling outcome frequency via the P3, RewP amplitudes were larger in reward trials than in neutral trials across incremental stages of goal pursuit. The RewP appears to be sensitive to feedback indicating successfully completing sub-goals during pursuit of a goal, even when no immediate reward is given. Approach motivation enhances performance monitoring when multiple steps are needed to attain a desired outcome, which may increase the likelihood of goal acquisition and attainment. Copyright © 2017 Elsevier B.V. All rights reserved.

Aspects of random geometric graphs : Pursuit-evasion and treewidth

NARCIS (Netherlands)

Li, A.

2015-01-01

In this thesis, we studied two aspects of random geometric graphs: pursuit-evasion and treewidth. We first studied one pursuit-evasion game: Cops and Robbers. This game, which dates back to 1970s, are studied extensively in recent years. We investigate this game on random geometric graphs, and get

Illusory motion reveals velocity matching, not foveation, drives smooth pursuit of large objects.

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Ma, Zheng; Watamaniuk, Scott N J; Heinen, Stephen J

2017-10-01

When small objects move in a scene, we keep them foveated with smooth pursuit eye movements. Although large objects such as people and animals are common, it is nonetheless unknown how we pursue them since they cannot be foveated. It might be that the brain calculates an object's centroid, and then centers the eyes on it during pursuit as a foveation mechanism might. Alternatively, the brain merely matches the velocity by motion integration. We test these alternatives with an illusory motion stimulus that translates at a speed different from its retinal motion. The stimulus was a Gabor array that translated at a fixed velocity, with component Gabors that drifted with motion consistent or inconsistent with the translation. Velocity matching predicts different pursuit behaviors across drift conditions, while centroid matching predicts no difference. We also tested whether pursuit can segregate and ignore irrelevant local drifts when motion and centroid information are consistent by surrounding the Gabors with solid frames. Finally, observers judged the global translational speed of the Gabors to determine whether smooth pursuit and motion perception share mechanisms. We found that consistent Gabor motion enhanced pursuit gain while inconsistent, opposite motion diminished it, drawing the eyes away from the center of the stimulus and supporting a motion-based pursuit drive. Catch-up saccades tended to counter the position offset, directing the eyes opposite to the deviation caused by the pursuit gain change. Surrounding the Gabors with visible frames canceled both the gain increase and the compensatory saccades. Perceived speed was modulated analogous to pursuit gain. The results suggest that smooth pursuit of large stimuli depends on the magnitude of integrated retinal motion information, not its retinal location, and that the position system might be unnecessary for generating smooth velocity to large pursuit targets.

Multiagent Cooperative Learning Strategies for Pursuit-Evasion Games

Directory of Open Access Journals (Sweden)

Jong Yih Kuo

2015-01-01

Full Text Available This study examines the pursuit-evasion problem for coordinating multiple robotic pursuers to locate and track a nonadversarial mobile evader in a dynamic environment. Two kinds of pursuit strategies are proposed, one for agents that cooperate with each other and the other for agents that operate independently. This work further employs the probabilistic theory to analyze the uncertain state information about the pursuers and the evaders and uses case-based reasoning to equip agents with memories and learning abilities. According to the concepts of assimilation and accommodation, both positive-angle and bevel-angle strategies are developed to assist agents in adapting to their environment effectively. The case study analysis uses the Recursive Porous Agent Simulation Toolkit (REPAST to implement a multiagent system and demonstrates superior performance of the proposed approaches to the pursuit-evasion game.

Dynamics of multiple-goal pursuit.

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Louro, Maria J; Pieters, Rik; Zeelenberg, Marcel

2007-08-01

The authors propose and test a model of multiple-goal pursuit that specifies how individuals allocate effort among multiple goals over time. The model predicts that whether individuals decide to step up effort, coast, abandon the current goal, or switch to pursue another goal is determined jointly by the emotions that flow from prior goal progress and the proximity to future goal attainment, and proximally determined by changes in expectancies about goal attainment. Results from a longitudinal diary study and 2 experiments show that positive and negative goal-related emotions can have diametrically opposing effects on goal-directed behavior, depending on the individual's proximity to goal attainment. The findings resolve contrasting predictions about the influence of positive and negative emotions in volitional behavior, critically amend the goal gradient hypothesis, and provide new insights into the dynamics and determinants of multiple-goal pursuit.

Role of retinal slip in the prediction of target motion during smooth and saccadic pursuit.

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de Brouwer, S; Missal, M; Lefèvre, P

2001-08-01

Visual tracking of moving targets requires the combination of smooth pursuit eye movements with catch-up saccades. In primates, catch-up saccades usually take place only during pursuit initiation because pursuit gain is close to unity. This contrasts with the lower and more variable gain of smooth pursuit in cats, where smooth eye movements are intermingled with catch-up saccades during steady-state pursuit. In this paper, we studied in detail the role of retinal slip in the prediction of target motion during smooth and saccadic pursuit in the cat. We found that the typical pattern of pursuit in the cat was a combination of smooth eye movements with saccades. During smooth pursuit initiation, there was a correlation between peak eye acceleration and target velocity. During pursuit maintenance, eye velocity oscillated at approximately 3 Hz around a steady-state value. The average gain of smooth pursuit was approximately 0.5. Trained cats were able to continue pursuing in the absence of a visible target, suggesting a role of the prediction of future target motion in this species. The analysis of catch-up saccades showed that the smooth-pursuit motor command is added to the saccadic command during catch-up saccades and that both position error and retinal slip are taken into account in their programming. The influence of retinal slip on catch-up saccades showed that prediction about future target motion is used in the programming of catch-up saccades. Altogether, these results suggest that pursuit systems in primates and cats are qualitatively similar, with a lower average gain in the cat and that prediction affects both saccades and smooth eye movements during pursuit.

Landscape ecological security assessment based on projection pursuit in Pearl River Delta.

Science.gov (United States)

Gao, Yang; Wu, Zhifeng; Lou, Quansheng; Huang, Huamei; Cheng, Jiong; Chen, Zhangli

2012-04-01

Regional landscape ecological security is an important issue for ecological security, and has a great influence on national security and social sustainable development. The Pearl River Delta (PRD) in southern China has experienced rapid economic development and intensive human activities in recent years. This study, based on landscape analysis, provides a method to discover the alteration of character among different landscape types and to understand the landscape ecological security status. Based on remotely sensed products of the Landsat 5 TM images in 1990 and the Landsat 7 ETM+ images in 2005, landscape classification maps of nine cities in the PRD were compiled by implementing Remote Sensing and Geographic Information System technology. Several indices, including aggregation, crush index, landscape shape index, Shannon's diversity index, landscape fragile index, and landscape security adjacent index, were applied to analyze spatial-temporal characteristics of landscape patterns in the PRD. A landscape ecological security index based on these outcomes was calculated by projection pursuit using genetic algorithm. The landscape ecological security of nine cities in the PRD was thus evaluated. The main results of this research are listed as follows: (1) from 1990 to 2005, the aggregation index, crush index, landscape shape index, and Shannon's diversity index of nine cities changed little in the PRD, while the landscape fragile index and landscape security adjacent index changed obviously. The landscape fragile index of nine cities showed a decreasing trend; however, the landscape security adjacent index has been increasing; (2) from 1990 to 2005, landscape ecology of the cities of Zhuhai and Huizhou maintained a good security situation. However, there was a relatively low value of ecological security in the cities of Dongguan and Foshan. Except for Foshan and Guangzhou, whose landscape ecological security situation were slightly improved, the cities had reduced

Influence of positive subliminal and supraliminal affective cues on goal pursuit in schizophrenia

NARCIS (Netherlands)

Chaillou, Anne Clémence; Giersch, Anne; Bonnefond, Anne; Custers, Ruud; Capa, Rémi L.

2015-01-01

Goal pursuit is known to be impaired in schizophrenia, but nothing much is known in these patients about unconscious affective processes underlying goal pursuit. Evidence suggests that in healthy individuals positive subliminal cues are taken as a signal that goal pursuit is easy and therefore

Receptive fields for smooth pursuit eye movements and motion perception.

Science.gov (United States)

Debono, Kurt; Schütz, Alexander C; Spering, Miriam; Gegenfurtner, Karl R

2010-12-01

Humans use smooth pursuit eye movements to track moving objects of interest. In order to track an object accurately, motion signals from the target have to be integrated and segmented from motion signals in the visual context. Most studies on pursuit eye movements used small visual targets against a featureless background, disregarding the requirements of our natural visual environment. Here, we tested the ability of the pursuit and the perceptual system to integrate motion signals across larger areas of the visual field. Stimuli were random-dot kinematograms containing a horizontal motion signal, which was perturbed by a spatially localized, peripheral motion signal. Perturbations appeared in a gaze-contingent coordinate system and had a different direction than the main motion including a vertical component. We measured pursuit and perceptual direction discrimination decisions and found that both steady-state pursuit and perception were influenced most by perturbation angles close to that of the main motion signal and only in regions close to the center of gaze. The narrow direction bandwidth (26 angular degrees full width at half height) and small spatial extent (8 degrees of visual angle standard deviation) correspond closely to tuning parameters of neurons in the middle temporal area (MT). Copyright © 2010 Elsevier Ltd. All rights reserved.

Shared sensory estimates for human motion perception and pursuit eye movements.

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Mukherjee, Trishna; Battifarano, Matthew; Simoncini, Claudio; Osborne, Leslie C

2015-06-03

Are sensory estimates formed centrally in the brain and then shared between perceptual and motor pathways or is centrally represented sensory activity decoded independently to drive awareness and action? Questions about the brain's information flow pose a challenge because systems-level estimates of environmental signals are only accessible indirectly as behavior. Assessing whether sensory estimates are shared between perceptual and motor circuits requires comparing perceptual reports with motor behavior arising from the same sensory activity. Extrastriate visual cortex both mediates the perception of visual motion and provides the visual inputs for behaviors such as smooth pursuit eye movements. Pursuit has been a valuable testing ground for theories of sensory information processing because the neural circuits and physiological response properties of motion-responsive cortical areas are well studied, sensory estimates of visual motion signals are formed quickly, and the initiation of pursuit is closely coupled to sensory estimates of target motion. Here, we analyzed variability in visually driven smooth pursuit and perceptual reports of target direction and speed in human subjects while we manipulated the signal-to-noise level of motion estimates. Comparable levels of variability throughout viewing time and across conditions provide evidence for shared noise sources in the perception and action pathways arising from a common sensory estimate. We found that conditions that create poor, low-gain pursuit create a discrepancy between the precision of perception and that of pursuit. Differences in pursuit gain arising from differences in optic flow strength in the stimulus reconcile much of the controversy on this topic. Copyright © 2015 the authors 0270-6474/15/358515-16$15.00/0.

Contextual effects on motion perception and smooth pursuit eye movements.

Science.gov (United States)

Spering, Miriam; Gegenfurtner, Karl R

2008-08-15

Smooth pursuit eye movements are continuous, slow rotations of the eyes that allow us to follow the motion of a visual object of interest. These movements are closely related to sensory inputs from the visual motion processing system. To track a moving object in the natural environment, its motion first has to be segregated from the motion signals provided by surrounding stimuli. Here, we review experiments on the effect of the visual context on motion processing with a focus on the relationship between motion perception and smooth pursuit eye movements. While perception and pursuit are closely linked, we show that they can behave quite distinctly when required by the visual context.

Contrast and assimilation in motion perception and smooth pursuit eye movements.

Science.gov (United States)

Spering, Miriam; Gegenfurtner, Karl R

2007-09-01

The analysis of visual motion serves many different functions ranging from object motion perception to the control of self-motion. The perception of visual motion and the oculomotor tracking of a moving object are known to be closely related and are assumed to be controlled by shared brain areas. We compared perceived velocity and the velocity of smooth pursuit eye movements in human observers in a paradigm that required the segmentation of target object motion from context motion. In each trial, a pursuit target and a visual context were independently perturbed simultaneously to briefly increase or decrease in speed. Observers had to accurately track the target and estimate target speed during the perturbation interval. Here we show that the same motion signals are processed in fundamentally different ways for perception and steady-state smooth pursuit eye movements. For the computation of perceived velocity, motion of the context was subtracted from target motion (motion contrast), whereas pursuit velocity was determined by the motion average (motion assimilation). We conclude that the human motion system uses these computations to optimally accomplish different functions: image segmentation for object motion perception and velocity estimation for the control of smooth pursuit eye movements.

Narcissism and the Strategic Pursuit of Short-Term Mating

DEFF Research Database (Denmark)

Schmitt, David P.; Alcalay, Lidia; Allik, Jüri

2017-01-01

Previous studies have documented links between sub-clinical narcissism and the active pursuit of short-term mating strategies (e.g., unrestricted sociosexuality, marital infidelity, mate poaching). Nearly all of these investigations have relied solely on samples from Western cultures. In the curr...... limitations of these cross-culturally universal findings and presents suggestions for future research into revealing the precise psychological features of narcissism that facilitate the strategic pursuit of short-term mating....

Coordinated Control of Three-Dimensional Components of Smooth Pursuit to Rotating and Translating Textures.

Science.gov (United States)

Edinger, Janick; Pai, Dinesh K; Spering, Miriam

2017-01-01

The neural control of pursuit eye movements to visual textures that simultaneously translate and rotate has largely been neglected. Here we propose that pursuit of such targets-texture pursuit-is a fully three-dimensional task that utilizes all three degrees of freedom of the eye, including torsion. Head-fixed healthy human adults (n = 8) tracked a translating and rotating random dot pattern, shown on a computer monitor, with their eyes. Horizontal, vertical, and torsional eye positions were recorded with a head-mounted eye tracker. The torsional component of pursuit is a function of the rotation of the texture, aligned with its visual properties. We observed distinct behaviors between those trials in which stimulus rotation was in the same direction as that of a rolling ball ("natural") in comparison to those with the opposite rotation ("unnatural"): Natural rotation enhanced and unnatural rotation reversed torsional velocity during pursuit, as compared to torsion triggered by a nonrotating random dot pattern. Natural rotation also triggered pursuit with a higher horizontal velocity gain and fewer and smaller corrective saccades. Furthermore, we show that horizontal corrective saccades are synchronized with torsional corrective saccades, indicating temporal coupling of horizontal and torsional saccade control. Pursuit eye movements have a torsional component that depends on the visual stimulus. Horizontal and torsional eye movements are separated in the motor periphery. Our findings suggest that translational and rotational motion signals might be coordinated in descending pursuit pathways.

Linear Pursuit Differential Game under Phase Constraint on the State of Evader

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Askar Rakhmanov

2016-01-01

Full Text Available We consider a linear pursuit differential game of one pursuer and one evader. Controls of the pursuer and evader are subjected to integral and geometric constraints, respectively. In addition, phase constraint is imposed on the state of evader, whereas pursuer moves throughout the space. We say that pursuit is completed, if inclusion y(t1-x(t1∈M is satisfied at some t1>0, where x(t and y(t are states of pursuer and evader, respectively, and M is terminal set. Conditions of completion of pursuit in the game from all initial points of players are obtained. Strategy of the pursuer is constructed so that the phase vector of the pursuer first is brought to a given set, and then pursuit is completed.

Optimized Projection Matrix for Compressive Sensing

Directory of Open Access Journals (Sweden)

Jianping Xu

2010-01-01

Full Text Available Compressive sensing (CS is mainly concerned with low-coherence pairs, since the number of samples needed to recover the signal is proportional to the mutual coherence between projection matrix and sparsifying matrix. Until now, papers on CS always assume the projection matrix to be a random matrix. In this paper, aiming at minimizing the mutual coherence, a method is proposed to optimize the projection matrix. This method is based on equiangular tight frame (ETF design because an ETF has minimum coherence. It is impossible to solve the problem exactly because of the complexity. Therefore, an alternating minimization type method is used to find a feasible solution. The optimally designed projection matrix can further reduce the necessary number of samples for recovery or improve the recovery accuracy. The proposed method demonstrates better performance than conventional optimization methods, which brings benefits to both basis pursuit and orthogonal matching pursuit.

Competition between color and luminance for target selection in smooth pursuit and saccadic eye movements.

Science.gov (United States)

Spering, Miriam; Montagnini, Anna; Gegenfurtner, Karl R

2008-11-24

Visual processing of color and luminance for smooth pursuit and saccadic eye movements was investigated using a target selection paradigm. In two experiments, stimuli were varied along the dimensions color and luminance, and selection of the more salient target was compared in pursuit and saccades. Initial pursuit was biased in the direction of the luminance component whereas saccades showed a relative preference for color. An early pursuit response toward luminance was often reversed to color by a later saccade. Observers' perceptual judgments of stimulus salience, obtained in two control experiments, were clearly biased toward luminance. This choice bias in perceptual data implies that the initial short-latency pursuit response agrees with perceptual judgments. In contrast, saccades, which have a longer latency than pursuit, do not seem to follow the perceptual judgment of salience but instead show a stronger relative preference for color. These substantial differences in target selection imply that target selection processes for pursuit and saccadic eye movements use distinctly different weights for color and luminance stimuli.

Automatic Epileptic Seizure Onset Detection Using Matching Pursuit

DEFF Research Database (Denmark)

Sorensen, Thomas Lynggaard; Olsen, Ulrich L.; Conradsen, Isa

2010-01-01

. The combination of Matching Pursuit and SVM for automatic seizure detection has never been tested before, making this a pilot study. Data from red different patients with 6 to 49 seizures are used to test our model. Three patients are recorded with scalp electroencephalography (sEEG) and three with intracranial...... electroencephalography (iEEG). A sensitivity of 78-100% and a detection latency of 5-18s has been achieved, while holding the false detection at 0.16-5.31/h. Our results show the potential of Matching Pursuit as a feature xtractor for detection of epileptic seizures....

Pursuit Latency for Chromatic Targets

Science.gov (United States)

Mulligan, Jeffrey B.; Ellis, Stephen R. (Technical Monitor)

1998-01-01

The temporal dynamics of eye movement response to a change in direction of stimulus motion has been used to compare the processing speeds of different types of stimuli (Mulligan, ARVO '97). In this study, the pursuit response to colored targets was measured to test the hypothesis that the slow response of the chromatic system (as measured using traditional temporal sensitivity measures such as contrast sensitivity) results in increased eye movement latencies. Subjects viewed a small (0.4 deg) Gaussian spot which moved downward at a speed of 6.6 deg/sec. At a variable time during the trajectory, the dot's direction of motion changed by 30 degrees, either to the right or left. Subjects were instructed to pursue the spot. Eye movements were measured using a video ophthalmoscope with an angular resolution of approximately 1 arc min and a temporal sampling rate of 60 Hz. Stimuli were modulated in chrominance for a variety of hue directions, combined with a range of small luminance increments and decrements, to insure that some of the stimuli fell in the subjects' equiluminance planes. The smooth portions of the resulting eye movement traces were fit by convolving the stimulus velocity with an exponential having variable onset latency, time constant and amplitude. Smooth eye movements with few saccades were observed for all stimuli. Pursuit responses to stimuli having a significant luminance component are well-fit by exponentials having latencies and time constants on the order of 100 msec. Increases in pursuit response latency on the order of 100-200 msec are observed in response to certain stimuli, which occur in pairs of complementary hues, corresponding to the intersection of the stimulus section with the subjects' equiluminant plane. Smooth eye movements can be made in response to purely chromatic stimuli, but are slower than responses to stimuli with a luminance component.

Toward Simulating Realistic Pursuit-Evasion Using a Roadmap-Based Approach

KAUST Repository

Rodriguez, Samuel

2010-01-01

In this work, we describe an approach for modeling and simulating group behaviors for pursuit-evasion that uses a graph-based representation of the environment and integrates multi-agent simulation with roadmap-based path planning. We demonstrate the utility of this approach for a variety of scenarios including pursuit-evasion on terrains, in multi-level buildings, and in crowds. © 2010 Springer-Verlag Berlin Heidelberg.

Predicting 2D target velocity cannot help 2D motion integration for smooth pursuit initiation.

Science.gov (United States)

Montagnini, Anna; Spering, Miriam; Masson, Guillaume S

2006-12-01

Smooth pursuit eye movements reflect the temporal dynamics of bidimensional (2D) visual motion integration. When tracking a single, tilted line, initial pursuit direction is biased toward unidimensional (1D) edge motion signals, which are orthogonal to the line orientation. Over 200 ms, tracking direction is slowly corrected to finally match the 2D object motion during steady-state pursuit. We now show that repetition of line orientation and/or motion direction does not eliminate the transient tracking direction error nor change the time course of pursuit correction. Nonetheless, multiple successive presentations of a single orientation/direction condition elicit robust anticipatory pursuit eye movements that always go in the 2D object motion direction not the 1D edge motion direction. These results demonstrate that predictive signals about target motion cannot be used for an efficient integration of ambiguous velocity signals at pursuit initiation.

Contributions to Pursuit-Evasion Game Theory

Science.gov (United States)

Oyler, Dave Wilson

This dissertation studies adversarial conflicts among a group of agents moving in the plane, possibly among obstacles, where some agents are pursuers and others are evaders. The goal of the pursuers is to capture the evaders, where capture requires a pursuer to be either co-located with an evader, or in close proximity. The goal of the evaders is to avoid capture. These scenarios, where different groups compete to accomplish conflicting goals, are referred to as pursuit-evasion games, and the agents are called players. Games featuring one pursuer and one evader are analyzed using dominance, where a point in the plane is said to be dominated by a player if that player is able to reach the point before the opposing players, regardless of the opposing players' actions. Two generalizations of the Apollonius circle are provided. One solves games with environments containing obstacles, and the other provides an alternative solution method for the Homicidal Chauffeur game. Optimal pursuit and evasion strategies based on dominance are provided. One benefit of dominance analysis is that it extends to games with many players. Two foundational games are studied; one features multiple pursuers against a single evader, and the other features a single pursuer against multiple evaders. Both are solved using dominance through a reduction to single pursuer, single evader games. Another game featuring competing teams of pursuers is introduced, where an evader cooperates with friendly pursuers to rendezvous before being captured by adversaries. Next, the assumption of complete and perfect information is relaxed, and uncertainties in player speeds, player positions, obstacle locations, and cost functions are studied. The sensitivity of the dominance boundary to perturbations in parameters is provided, and probabilistic dominance is introduced. The effect of information is studied by comparing solutions of games with perfect information to games with uncertainty. Finally, a pursuit law

Research on multirobot pursuit task allocation algorithm based on emotional cooperation factor.

Science.gov (United States)

Fang, Baofu; Chen, Lu; Wang, Hao; Dai, Shuanglu; Zhong, Qiubo

2014-01-01

Multirobot task allocation is a hot issue in the field of robot research. A new emotional model is used with the self-interested robot, which gives a new way to measure self-interested robots' individual cooperative willingness in the problem of multirobot task allocation. Emotional cooperation factor is introduced into self-interested robot; it is updated based on emotional attenuation and external stimuli. Then a multirobot pursuit task allocation algorithm is proposed, which is based on emotional cooperation factor. Combined with the two-step auction algorithm recruiting team leaders and team collaborators, set up pursuit teams, and finally use certain strategies to complete the pursuit task. In order to verify the effectiveness of this algorithm, some comparing experiments have been done with the instantaneous greedy optimal auction algorithm; the results of experiments show that the total pursuit time and total team revenue can be optimized by using this algorithm.

Relative Effects of Forward and Backward Planning on Goal Pursuit.

Science.gov (United States)

Park, Jooyoung; Lu, Fang-Chi; Hedgcock, William M

2017-11-01

Considerable research has shown that planning plays an important role in goal pursuit. But how does the way people plan affect goal pursuit? Research on this question is scarce. In the current research, we examined how planning the steps required for goal attainment in chronological order (i.e., forward planning) and reverse chronological order (i.e., backward planning) influences individuals' motivation for and perceptions of goal pursuit. Compared with forward planning, backward planning not only led to greater motivation, higher goal expectancy, and less time pressure but also resulted in better goal-relevant performance. We further demonstrated that this motivational effect occurred because backward planning allowed people to think of tasks required to reach their goals more clearly, especially when goals were complex to plan. These findings suggest that the way people plan matters just as much as whether or not they plan.

Projection Pursuit Through ϕ-Divergence Minimisation

Directory of Open Access Journals (Sweden)

Jacques Touboul

2010-06-01

Full Text Available In his 1985 article (“Projection pursuit”, Huber demonstrates the interest of his method to estimate a density from a data set in a simple given case. He considers the factorization of density through a Gaussian component and some residual density. Huber’s work is based on maximizing Kullback–Leibler divergence. Our proposal leads to a new algorithm. Furthermore, we will also consider the case when the density to be factorized is estimated from an i.i.d. sample. We will then propose a test for the factorization of the estimated density. Applications include a new test of fit pertaining to the elliptical copulas.

Research on Multirobot Pursuit Task Allocation Algorithm Based on Emotional Cooperation Factor

Directory of Open Access Journals (Sweden)

Baofu Fang

2014-01-01

Full Text Available Multirobot task allocation is a hot issue in the field of robot research. A new emotional model is used with the self-interested robot, which gives a new way to measure self-interested robots’ individual cooperative willingness in the problem of multirobot task allocation. Emotional cooperation factor is introduced into self-interested robot; it is updated based on emotional attenuation and external stimuli. Then a multirobot pursuit task allocation algorithm is proposed, which is based on emotional cooperation factor. Combined with the two-step auction algorithm recruiting team leaders and team collaborators, set up pursuit teams, and finally use certain strategies to complete the pursuit task. In order to verify the effectiveness of this algorithm, some comparing experiments have been done with the instantaneous greedy optimal auction algorithm; the results of experiments show that the total pursuit time and total team revenue can be optimized by using this algorithm.

Expansion of direction space around the cardinal axes revealed by smooth pursuit eye movements

Science.gov (United States)

Krukowski, Anton E.; Stone, Leland S.

2005-01-01

It is well established that perceptual direction discrimination shows an oblique effect; thresholds are higher for motion along diagonal directions than for motion along cardinal directions. Here, we compare simultaneous direction judgments and pursuit responses for the same motion stimuli and find that both pursuit and perceptual thresholds show similar anisotropies. The pursuit oblique effect is robust under a wide range of experimental manipulations, being largely resistant to changes in trajectory (radial versus tangential motion), speed (10 versus 25 deg/s), directional uncertainty (blocked versus randomly interleaved), and cognitive state (tracking alone versus concurrent tracking and perceptual tasks). Our data show that the pursuit oblique effect is caused by an effective expansion of direction space surrounding the cardinal directions and the requisite compression of space for other directions. This expansion suggests that the directions around the cardinal directions are in some way overrepresented in the visual cortical pathways that drive both smooth pursuit and perception.

Pursuit-evasion differential games

CERN Document Server

Yavin, Y

1987-01-01

Twenty papers are devoted to the treatment of a wide spectrum of problems in the theory and applications of dynamic games with the emphasis on pursuit-evasion differential games. The problem of capturability is thoroughly investigated, also the problem of noise-corrupted (state) measurements. Attention is given to aerial combat problems and their attendant modelling issues, such as variable speed of the combatants, the three-dimensionality of physical space, and the combat problem, i.e. problems related to 'role determination'.

Are altered smooth pursuit eye movements related to chronic pain and disability following whiplash injuries? A prospective trial with one-year follow-up

DEFF Research Database (Denmark)

Kongsted, Alice; Jørgensen, Lars Vincents; Leboeuf-Yde, Charlotte

2008-01-01

collision were determined. RESULTS: Results of early eye movement tests were not associated with the prognosis. Reduced smooth pursuit performance when tested in static cervical rotation at the one-year follow-up was significantly associated with higher neck pain intensity at that time (regression...... with electrooculography (EOG) an average of 12 days after a whiplash trauma and again after one year. Analyses of EOG recordings were computerized. Associations between test results both from baseline and one-year tests and self-reported neck pain, headache, neck disability and working ability one year after the car...... coefficient 0.8, 95% confidence interval (CI) 0.04-1.5), but the association was too weak for the test to discriminate between recovered participants and those with lasting symptoms. CONCLUSIONS: Although reduced smooth pursuit performance at one-year follow-up was associated with persistent neck pain, smooth...

Narcissism and the Strategic Pursuit of Short-Term Mating: Universal Links across 11 World Regions of the International Sexuality Description Project-2

Directory of Open Access Journals (Sweden)

David P. Schmitt et al.

2017-05-01

Full Text Available Previous studies have documented links between sub-clinical narcissism and the active pursuit of short-term mating strategies (e.g., unrestricted sociosexuality, marital infidelity, mate poaching. Nearly all of these investigations have relied solely on samples from Western cultures. In the current study, responses from a cross-cultural survey of 30,470 people across 53 nations spanning 11 world regions (North America, Central/South America, Northern Europe, Western Europe, Eastern Europe, Southern Europe, Middle East, Africa, Oceania, Southeast Asia, and East Asia were used to evaluate whether narcissism (as measured by the Narcissistic Personality Inventory; NPI was universally associated with short-term mating. Results revealed narcissism scores (including two broad factors and seven traditional facets as measured by the NPI were functionally equivalent across cultures, reliably associating with key sexual outcomes (e.g., more active pursuit of short-term mating, intimate partner violence, and sexual aggression and sex-related personality traits (e.g., higher extraversion and openness to experience. Whereas some features of personality (e.g., subjective well-being were universally associated with socially adaptive facets of Narcissism (e.g., self-sufficiency, most indicators of short-term mating (e.g., unrestricted sociosexuality and marital infidelity were universally associated with the socially maladaptive facets of narcissism (e.g., exploitativeness. Discussion addresses limitations of these cross-culturally universal findings and presents suggestions for future research into revealing the precise psychological features of narcissism that facilitate the strategic pursuit of short-term mating.

Graduate Management Project. The Pursuit of Quality in Military Health Care: Are We Held to a Higher Standard?

Science.gov (United States)

2006-06-20

end in itself, a final cause of seeking the good in other pursuits (Abelson & Nielsen, 1967). Immanuel Kant’s ideas also have a significant influence...on ethics. Kant defined ethics as the philosophical science that "... deals with the laws of free moral action" ( Kant , 1964, p. 13). Kant’s ethical...Organization, (n.d.). Biography of the Honorable William Winkenwerder, Jr., M.D., MB.A., Assistant Secretary of Defense for Health Affairs. Retrieved

The Pursuit of Excellence through Education.

Science.gov (United States)

Ferrari, Michel, Ed.

In this book theorists and researchers present a range of perspectives on how to promote excellence in education, providing an opportunity for expression to those who stress transformation of educational practice and those who emphasize individual abilities. In part 1, The Individual Pursuit of Excellence, the chapters are: (1) Learning from…

The aesthetic and cultural pursuits of patients with stroke.

Science.gov (United States)

O'Connell, Clare; Cassidy, Aoife; O'Neill, Desmond; Moss, Hilary

2013-11-01

There has been an increasing interest in the arts in health care, with a suggestion that the arts and aesthetics can augment patient outcomes in stroke and other illnesses. Designing such programmes requires better knowledge of the artistic, aesthetic, and cultural pursuits of people affected by stroke. The aim of this study was to obtain the insights of this group about the profile of art and aesthetic activities in their lives and the influence of stroke on these aspects. Patients attending a stroke service were administered questions adapted from the Irish Arts Council's 2006 questionnaire on participation in aesthetics and cultural pursuits. Information was also collected on stroke type and present functional and cognitive status. Thirty-eight patients were interviewed. Of these, 20 were inpatients in hospital at the time of the interview and 18 were interviewed in an outpatient setting. Popular activities included mainstream cinema, listening to music, dancing, attending plays or musicals, and being outdoors. Many patients ceased these activities after their stroke, mostly because of health issues and inaccessibility. Most of the patients valued the importance of the arts in the health-care setting. This study gives a perspective for the first time on the aesthetic and cultural pursuits of stroke patients before their stroke. It portrays a wide variety of cultural and leisure activities and the cessation of these poststroke. It revealed the restrictions patients felt on gaining access to leisure pursuits both while in hospital and following discharge. Copyright © 2013 National Stroke Association. Published by Elsevier Inc. All rights reserved.

SU-G-BRA-08: Diaphragm Motion Tracking Based On KV CBCT Projections with a Constrained Linear Regression Optimization

Energy Technology Data Exchange (ETDEWEB)

Wei, J [City College of New York, New York, NY (United States); Chao, M [The Mount Sinai Medical Center, New York, NY (United States)

2016-06-15

Purpose: To develop a novel strategy to extract the respiratory motion of the thoracic diaphragm from kilovoltage cone beam computed tomography (CBCT) projections by a constrained linear regression optimization technique. Methods: A parabolic function was identified as the geometric model and was employed to fit the shape of the diaphragm on the CBCT projections. The search was initialized by five manually placed seeds on a pre-selected projection image. Temporal redundancies, the enabling phenomenology in video compression and encoding techniques, inherent in the dynamic properties of the diaphragm motion together with the geometrical shape of the diaphragm boundary and the associated algebraic constraint that significantly reduced the searching space of viable parabolic parameters was integrated, which can be effectively optimized by a constrained linear regression approach on the subsequent projections. The innovative algebraic constraints stipulating the kinetic range of the motion and the spatial constraint preventing any unphysical deviations was able to obtain the optimal contour of the diaphragm with minimal initialization. The algorithm was assessed by a fluoroscopic movie acquired at anteriorposterior fixed direction and kilovoltage CBCT projection image sets from four lung and two liver patients. The automatic tracing by the proposed algorithm and manual tracking by a human operator were compared in both space and frequency domains. Results: The error between the estimated and manual detections for the fluoroscopic movie was 0.54mm with standard deviation (SD) of 0.45mm, while the average error for the CBCT projections was 0.79mm with SD of 0.64mm for all enrolled patients. The submillimeter accuracy outcome exhibits the promise of the proposed constrained linear regression approach to track the diaphragm motion on rotational projection images. Conclusion: The new algorithm will provide a potential solution to rendering diaphragm motion and ultimately

SU-G-BRA-08: Diaphragm Motion Tracking Based On KV CBCT Projections with a Constrained Linear Regression Optimization

International Nuclear Information System (INIS)

Wei, J; Chao, M

2016-01-01

Purpose: To develop a novel strategy to extract the respiratory motion of the thoracic diaphragm from kilovoltage cone beam computed tomography (CBCT) projections by a constrained linear regression optimization technique. Methods: A parabolic function was identified as the geometric model and was employed to fit the shape of the diaphragm on the CBCT projections. The search was initialized by five manually placed seeds on a pre-selected projection image. Temporal redundancies, the enabling phenomenology in video compression and encoding techniques, inherent in the dynamic properties of the diaphragm motion together with the geometrical shape of the diaphragm boundary and the associated algebraic constraint that significantly reduced the searching space of viable parabolic parameters was integrated, which can be effectively optimized by a constrained linear regression approach on the subsequent projections. The innovative algebraic constraints stipulating the kinetic range of the motion and the spatial constraint preventing any unphysical deviations was able to obtain the optimal contour of the diaphragm with minimal initialization. The algorithm was assessed by a fluoroscopic movie acquired at anteriorposterior fixed direction and kilovoltage CBCT projection image sets from four lung and two liver patients. The automatic tracing by the proposed algorithm and manual tracking by a human operator were compared in both space and frequency domains. Results: The error between the estimated and manual detections for the fluoroscopic movie was 0.54mm with standard deviation (SD) of 0.45mm, while the average error for the CBCT projections was 0.79mm with SD of 0.64mm for all enrolled patients. The submillimeter accuracy outcome exhibits the promise of the proposed constrained linear regression approach to track the diaphragm motion on rotational projection images. Conclusion: The new algorithm will provide a potential solution to rendering diaphragm motion and ultimately

Chases and escapes the mathematics of pursuit and evasion

CERN Document Server

Nahin, Paul J

2012-01-01

We all played tag when we were kids. What most of us don't realize is that this simple chase game is in fact an application of pursuit theory, and that the same principles of games like tag, dodgeball, and hide-and-seek are also at play in military strategy, high-seas chases by the Coast Guard, and even romantic pursuits. In Chases and Escapes, Paul Nahin gives us the first complete history of this fascinating area of mathematics, from its classical analytical beginnings to the present day. Drawing on game theory, geometry, linear algebra, target-tracking algorithms, and much

A New Approach of Multi-robot Cooperative Pursuit Based on Association Rule Data Mining

Directory of Open Access Journals (Sweden)

Jun Li

2010-02-01

Full Text Available An approach of cooperative hunting for multiple mobile targets by multi-robot is presented, which divides the pursuit process into forming the pursuit teams and capturing the targets. The data sets of attribute relationship is built by consulting all of factors about capturing evaders, then the interesting rules can be found by data mining from the data sets to build the pursuit teams. Through doping out the positions of targets, the pursuit game can be transformed into multi-robot path planning. Reinforcement learning is used to find the best path. The simulation results show that the mobile evaders can be captured effectively and efficiently, and prove the feasibility and validity of the given algorithm under a dynamic environment.

A New Approach of Multi-Robot Cooperative Pursuit Based on Association Rule Data Mining

Directory of Open Access Journals (Sweden)

Jun Li

2009-12-01

Full Text Available An approach of cooperative hunting for multiple mobile targets by multi-robot is presented, which divides the pursuit process into forming the pursuit teams and capturing the targets. The data sets of attribute relationship is built by consulting all of factors about capturing evaders, then the interesting rules can be found by data mining from the data sets to build the pursuit teams. Through doping out the positions of targets, the pursuit game can be transformed into multi-robot path planning. Reinforcement learning is used to find the best path. The simulation results show that the mobile evaders can be captured effectively and efficiently, and prove the feasibility and validity of the given algorithm under a dynamic environment.

Hierarchical brain networks active in approach and avoidance goal pursuit

Directory of Open Access Journals (Sweden)

Jeffrey Martin Spielberg

2013-06-01

Full Text Available Effective approach/avoidance goal pursuit is critical for attaining long-term health and well-being. Research on the neural correlates of key goal pursuit processes (e.g., motivation has long been of interest, with lateralization in prefrontal cortex being a particularly fruitful target of investigation. However, this literature has often been limited by a lack of spatial specificity and has not delineated the precise aspects of approach/avoidance motivation involved. Additionally, the relationships among brain regions (i.e., network connectivity vital to goal pursuit remain largely unexplored. Specificity in location, process, and network relationship is vital for moving beyond gross characterizations of function and identifying the precise cortical mechanisms involved in motivation. The present paper integrates research using more spatially specific methodologies (e.g., functional magnetic resonance imaging with the rich psychological literature on approach/avoidance to propose an integrative network model that takes advantage of the strengths of each of these literatures.

Hierarchical brain networks active in approach and avoidance goal pursuit.

Science.gov (United States)

Spielberg, Jeffrey M; Heller, Wendy; Miller, Gregory A

2013-01-01

Effective approach/avoidance goal pursuit is critical for attaining long-term health and well-being. Research on the neural correlates of key goal-pursuit processes (e.g., motivation) has long been of interest, with lateralization in prefrontal cortex being a particularly fruitful target of investigation. However, this literature has often been limited by a lack of spatial specificity and has not delineated the precise aspects of approach/avoidance motivation involved. Additionally, the relationships among brain regions (i.e., network connectivity) vital to goal-pursuit remain largely unexplored. Specificity in location, process, and network relationship is vital for moving beyond gross characterizations of function and identifying the precise cortical mechanisms involved in motivation. The present paper integrates research using more spatially specific methodologies (e.g., functional magnetic resonance imaging) with the rich psychological literature on approach/avoidance to propose an integrative network model that takes advantage of the strengths of each of these literatures.

Narcissism and the Strategic Pursuit of Short-Term Mating : Pervasive Links across 11 World Regions of the International Sexuality Description Project-2

NARCIS (Netherlands)

Schmitt, David; Vanwesenbeeck, W.M.A.

2017-01-01

Previous studies have documented links between sub-clinical narcissism and the active pursuit of short-term mating strategies (e.g., unrestricted sociosexuality, marital infidelity, mate poaching). Nearly all of these investigations have relied solely on samples from Western cultures. In the current

Experimental evaluation of user performance in a pursuit tracking task with multimodal feedback

Directory of Open Access Journals (Sweden)

Obrenović Željko

2004-01-01

Full Text Available In this paper we describe the results of experimental evaluation of user performance in a pursuit-tracking task with multimodal feedback. Our experimental results indicate that audio can significantly improve the accuracy of pursuit tracking. Experiments with 19 participants have shown that addition of acoustic modalities reduces the error during pursuit tracking for up to 19%. Moreover, experiments indicated the existence of perceptual boundaries of multimodal HCI for different scene complexity and target speeds. We have also shown that the most appealing paradigms are not the most effective ones, which necessitates a careful quantitative analysis of proposed multimodal HCI paradigms.

Reward action in the initiation of smooth pursuit eye movements

OpenAIRE

Joshua, Mati; Lisberger, Stephen G.

2012-01-01

Reward has a powerful influence on motor behavior. To probe how and where reward systems alter motor behavior, we studied smooth pursuit eye movements in monkeys trained to associate the color of a visual cue with the size of the reward to be issued at the end of the target motion. When the tracking task presented two different colored targets that moved orthogonally, monkeys biased the initiation of pursuit towards the direction of motion of the target that led to larger reward. The bias was...

A Pursuit Theory Account for the Perception of Common Motion in Motion Parallax.

Science.gov (United States)

Ratzlaff, Michael; Nawrot, Mark

2016-09-01

The visual system uses an extraretinal pursuit eye movement signal to disambiguate the perception of depth from motion parallax. Visual motion in the same direction as the pursuit is perceived nearer in depth while visual motion in the opposite direction as pursuit is perceived farther in depth. This explanation of depth sign applies to either an allocentric frame of reference centered on the fixation point or an egocentric frame of reference centered on the observer. A related problem is that of depth order when two stimuli have a common direction of motion. The first psychophysical study determined whether perception of egocentric depth order is adequately explained by a model employing an allocentric framework, especially when the motion parallax stimuli have common rather than divergent motion. A second study determined whether a reversal in perceived depth order, produced by a reduction in pursuit velocity, is also explained by this model employing this allocentric framework. The results show than an allocentric model can explain both the egocentric perception of depth order with common motion and the perceptual depth order reversal created by a reduction in pursuit velocity. We conclude that an egocentric model is not the only explanation for perceived depth order in these common motion conditions. © The Author(s) 2016.

Robust Matching Pursuit Extreme Learning Machines

Directory of Open Access Journals (Sweden)

Zejian Yuan

2018-01-01

Full Text Available Extreme learning machine (ELM is a popular learning algorithm for single hidden layer feedforward networks (SLFNs. It was originally proposed with the inspiration from biological learning and has attracted massive attentions due to its adaptability to various tasks with a fast learning ability and efficient computation cost. As an effective sparse representation method, orthogonal matching pursuit (OMP method can be embedded into ELM to overcome the singularity problem and improve the stability. Usually OMP recovers a sparse vector by minimizing a least squares (LS loss, which is efficient for Gaussian distributed data, but may suffer performance deterioration in presence of non-Gaussian data. To address this problem, a robust matching pursuit method based on a novel kernel risk-sensitive loss (in short KRSLMP is first proposed in this paper. The KRSLMP is then applied to ELM to solve the sparse output weight vector, and the new method named the KRSLMP-ELM is developed for SLFN learning. Experimental results on synthetic and real-world data sets confirm the effectiveness and superiority of the proposed method.

Simple Motion Pursuit and Evasion Differential Games with Many Pursuers on Manifolds with Euclidean Metric

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Atamurat Kuchkarov

2016-01-01

Full Text Available We consider pursuit and evasion differential games of a group of m pursuers and one evader on manifolds with Euclidean metric. The motions of all players are simple, and maximal speeds of all players are equal. If the state of a pursuer coincides with that of the evader at some time, we say that pursuit is completed. We establish that each of the differential games (pursuit or evasion is equivalent to a differential game of m groups of countably many pursuers and one group of countably many evaders in Euclidean space. All the players in any of these groups are controlled by one controlled parameter. We find a condition under which pursuit can be completed, and if this condition is not satisfied, then evasion is possible. We construct strategies for the pursuers in pursuit game which ensure completion the game for a finite time and give a formula for this time. In the case of evasion game, we construct a strategy for the evader.

Normal aging affects movement execution but not visual motion working memory and decision-making delay during cue-dependent memory-based smooth-pursuit.

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Fukushima, Kikuro; Barnes, Graham R; Ito, Norie; Olley, Peter M; Warabi, Tateo

2014-07-01

Aging affects virtually all functions including sensory/motor and cognitive activities. While retinal image motion is the primary input for smooth-pursuit, its efficiency/accuracy depends on cognitive processes. Elderly subjects exhibit gain decrease during initial and steady-state pursuit, but reports on latencies are conflicting. Using a cue-dependent memory-based smooth-pursuit task, we identified important extra-retinal mechanisms for initial pursuit in young adults including cue information priming and extra-retinal drive components (Ito et al. in Exp Brain Res 229:23-35, 2013). We examined aging effects on parameters for smooth-pursuit using the same tasks. Elderly subjects were tested during three task conditions as previously described: memory-based pursuit, simple ramp-pursuit just to follow motion of a single spot, and popping-out of the correct spot during memory-based pursuit to enhance retinal image motion. Simple ramp-pursuit was used as a task that did not require visual motion working memory. To clarify aging effects, we then compared the results with the previous young subject data. During memory-based pursuit, elderly subjects exhibited normal working memory of cue information. Most movement-parameters including pursuit latencies differed significantly between memory-based pursuit and simple ramp-pursuit and also between young and elderly subjects. Popping-out of the correct spot motion was ineffective for enhancing initial pursuit in elderly subjects. However, the latency difference between memory-based pursuit and simple ramp-pursuit in individual subjects, which includes decision-making delay in the memory task, was similar between the two groups. Our results suggest that smooth-pursuit latencies depend on task conditions and that, although the extra-retinal mechanisms were functional for initial pursuit in elderly subjects, they were less effective.

Keep your eyes on the ball: smooth pursuit eye movements enhance prediction of visual motion.

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Spering, Miriam; Schütz, Alexander C; Braun, Doris I; Gegenfurtner, Karl R

2011-04-01

Success of motor behavior often depends on the ability to predict the path of moving objects. Here we asked whether tracking a visual object with smooth pursuit eye movements helps to predict its motion direction. We developed a paradigm, "eye soccer," in which observers had to either track or fixate a visual target (ball) and judge whether it would have hit or missed a stationary vertical line segment (goal). Ball and goal were presented briefly for 100-500 ms and disappeared from the screen together before the perceptual judgment was prompted. In pursuit conditions, the ball moved towards the goal; in fixation conditions, the goal moved towards the stationary ball, resulting in similar retinal stimulation during pursuit and fixation. We also tested the condition in which the goal was fixated and the ball moved. Motion direction prediction was significantly better in pursuit than in fixation trials, regardless of whether ball or goal served as fixation target. In both fixation and pursuit trials, prediction performance was better when eye movements were accurate. Performance also increased with shorter ball-goal distance and longer presentation duration. A longer trajectory did not affect performance. During pursuit, an efference copy signal might provide additional motion information, leading to the advantage in motion prediction.

Avoidance goal pursuit depletes self-regulatory resources

NARCIS (Netherlands)

Oertig, D.; Schüler, J.; Schnelle, J.; Brandstätter, V.; Roskes, M.; Elliot, A.J.

2013-01-01

Objective: Research on the strength model of self-regulation is burgeoning, but little empirical work has focused on the link between distinct types of daily goal pursuit and the depletion of self-regulatory resources. Here we conducted two studies on the link between avoidance goals and resource

Avoidance goal pursuit depletes self-regulatory resources

NARCIS (Netherlands)

Oertig, Daniela; Schüler, Julia; Schnelle, Jessica; Brandstätter, Veronika; Roskes, Marieke; Elliot, Andrew J.

Objective: Research on the strength model of self-regulation is burgeoning, but little empirical work has focused on the link between distinct types of daily goal pursuit and the depletion of self-regulatory resources. The authors conducted two studies on the link between avoidance goals and

Attention is allocated closely ahead of the target during smooth pursuit eye movements: Evidence from EEG frequency tagging.

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Chen, Jing; Valsecchi, Matteo; Gegenfurtner, Karl R

2017-07-28

It is under debate whether attention during smooth pursuit is centered right on the pursuit target or allocated preferentially ahead of it. Attentional deployment was previously probed using a secondary task, which might have altered attention allocation and led to inconsistent findings. We measured frequency-tagged steady-state visual evoked potentials (SSVEP) to measure attention allocation in the absence of any secondary probing task. The observers pursued a moving dot while stimuli flickering at different frequencies were presented at various locations ahead or behind the pursuit target. We observed a significant increase in EEG power at the flicker frequency of the stimulus in front of the pursuit target, compared to the frequency of the stimulus behind. When testing many different locations, we found that the enhancement was detectable up to about 1.5° ahead during pursuit, but vanished by 3.5°. In a control condition using attentional cueing during fixation, we did observe an enhanced EEG response to stimuli at this eccentricity, indicating that the focus of attention during pursuit is narrower than allowed for by the resolution of the attentional system. In a third experiment, we ruled out the possibility that the SSVEP enhancement was a byproduct of the catch-up saccades occurring during pursuit. Overall, we showed that attention is on average allocated ahead of the pursuit target during smooth pursuit. EEG frequency tagging seems to be a powerful technique that allows for the investigation of attention/perception implicitly when an overt task would be confounding. Copyright © 2017 Elsevier Ltd. All rights reserved.

Engineering estimates versus impact evaluation of energy efficiency projects: Regression discontinuity evidence from a case study

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Lang, Corey; Siler, Matthew

2013-01-01

Energy efficiency upgrades have been gaining widespread attention across global channels as a cost-effective approach to addressing energy challenges. The cost-effectiveness of these projects is generally predicted using engineering estimates pre-implementation, often with little ex post analysis of project success. In this paper, for a suite of energy efficiency projects, we directly compare ex ante engineering estimates of energy savings to ex post econometric estimates that use 15-min interval, building-level energy consumption data. In contrast to most prior literature, our econometric results confirm the engineering estimates, even suggesting the engineering estimates were too modest. Further, we find heterogeneous efficiency impacts by time of day, suggesting select efficiency projects can be useful in reducing peak load. - Highlights: • Regression discontinuity used to estimate energy savings from efficiency projects. • Ex post econometric estimates validate ex ante engineering estimates of energy savings. • Select efficiency projects shown to reduce peak load

Discriminative Elastic-Net Regularized Linear Regression.

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Zhang, Zheng; Lai, Zhihui; Xu, Yong; Shao, Ling; Wu, Jian; Xie, Guo-Sen

2017-03-01

In this paper, we aim at learning compact and discriminative linear regression models. Linear regression has been widely used in different problems. However, most of the existing linear regression methods exploit the conventional zero-one matrix as the regression targets, which greatly narrows the flexibility of the regression model. Another major limitation of these methods is that the learned projection matrix fails to precisely project the image features to the target space due to their weak discriminative capability. To this end, we present an elastic-net regularized linear regression (ENLR) framework, and develop two robust linear regression models which possess the following special characteristics. First, our methods exploit two particular strategies to enlarge the margins of different classes by relaxing the strict binary targets into a more feasible variable matrix. Second, a robust elastic-net regularization of singular values is introduced to enhance the compactness and effectiveness of the learned projection matrix. Third, the resulting optimization problem of ENLR has a closed-form solution in each iteration, which can be solved efficiently. Finally, rather than directly exploiting the projection matrix for recognition, our methods employ the transformed features as the new discriminate representations to make final image classification. Compared with the traditional linear regression model and some of its variants, our method is much more accurate in image classification. Extensive experiments conducted on publicly available data sets well demonstrate that the proposed framework can outperform the state-of-the-art methods. The MATLAB codes of our methods can be available at http://www.yongxu.org/lunwen.html.

Altered velocity processing in schizophrenia during pursuit eye tracking.

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Matthias Nagel

Full Text Available Smooth pursuit eye movements (SPEM are needed to keep the retinal image of slowly moving objects within the fovea. Depending on the task, about 50%-80% of patients with schizophrenia have difficulties in maintaining SPEM. We designed a study that comprised different target velocities as well as testing for internal (extraretinal guidance of SPEM in the absence of a visual target. We applied event-related fMRI by presenting four velocities (5, 10, 15, 20°/s both with and without intervals of target blanking. 17 patients and 16 healthy participants were included. Eye movements were registered during scanning sessions. Statistical analysis included mixed ANOVAs and regression analyses of the target velocity on the Blood Oxygen Level Dependency (BOLD signal. The main effect group and the interaction of velocity×group revealed reduced activation in V5 and putamen but increased activation of cerebellar regions in patients. Regression analysis showed that activation in supplementary eye field, putamen, and cerebellum was not correlated to target velocity in patients in contrast to controls. Furthermore, activation in V5 and in intraparietal sulcus (putative LIP bilaterally was less strongly correlated to target velocity in patients than controls. Altered correlation of target velocity and neural activation in the cortical network supporting SPEM (V5, SEF, LIP, putamen implies impaired transformation of the visual motion signal into an adequate motor command in patients. Cerebellar regions seem to be involved in compensatory mechanisms although cerebellar activity in patients was not related to target velocity.

Sparse reconstruction using distribution agnostic bayesian matching pursuit

KAUST Repository

Masood, Mudassir; Al-Naffouri, Tareq Y.

2013-01-01

A fast matching pursuit method using a Bayesian approach is introduced for sparse signal recovery. This method performs Bayesian estimates of sparse signals even when the signal prior is non-Gaussian or unknown. It is agnostic on signal statistics

The Influence of Money on Goal Pursuit and Decision-Making: Understanding Money's Unique Impact on Goal Pursuit

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Moran, Nora

Previous research suggests that activating concepts of money and wealth can increase motivation to achieve personal goals. In this dissertation, I investigate how money affects pursuit of important personal goals, and how this motivation may be affected by goal attainability. In eight studies, I show that priming concepts of money and wealth leads individuals to pursue important personal goals to a greater degree than control groups, but only when a goal is more attainable. In contrast, when a goal is less attainable, those primed with money will be less likely to work towards goals relative to control groups. Furthermore, I examine why money may have a detrimental effect on motivation when individuals are faced with less attainable but important goals, and argue those primed with money become more concerned with maintaining a sense of efficacy, and thus disengage from pursuit when success is less certain. Thus, this research identifies the needs made salient by activating money--validating one's abilities. Finally, I show the relevance of these findings for consumer behavior, and discuss the additional implications of this work, as well as future research directions.

Distractor Interference during Smooth Pursuit Eye Movements

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Spering, Miriam; Gegenfurtner, Karl R.; Kerzel, Dirk

2006-01-01

When 2 targets for pursuit eye movements move in different directions, the eye velocity follows the vector average (S. G. Lisberger & V. P. Ferrera, 1997). The present study investigates the mechanisms of target selection when observers are instructed to follow a predefined horizontal target and to ignore a moving distractor stimulus. Results show…

Multi-target consensus circle pursuit for multi-agent systems via a distributed multi-flocking method

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Pei, Huiqin; Chen, Shiming; Lai, Qiang

2016-12-01

This paper studies the multi-target consensus pursuit problem of multi-agent systems. For solving the problem, a distributed multi-flocking method is designed based on the partial information exchange, which is employed to realise the pursuit of multi-target and the uniform distribution of the number of pursuing agents with the dynamic target. Combining with the proposed circle formation control strategy, agents can adaptively choose the target to form the different circle formation groups accomplishing a multi-target pursuit. The speed state of pursuing agents in each group converges to the same value. A Lyapunov approach is utilised to analyse the stability of multi-agent systems. In addition, a sufficient condition is given for achieving the dynamic target consensus pursuit, and which is then analysed. Finally, simulation results verify the effectiveness of the proposed approaches.

Toward realistic pursuit-evasion using a roadmap-based approach

KAUST Repository

Rodriguez, Samuel

2011-05-01

In this work, we describe an approach for modeling and simulating group behaviors for pursuit-evasion that uses a graph-based representation of the environment and integrates multi-agent simulation with roadmap-based path planning. Our approach can be applied to more realistic scenarios than are typically studied in most previous work, including agents moving in 3D environments such as terrains, multi-story buildings, and dynamic environments. We also support more realistic three-dimensional visibility computations that allow evading agents to hide in crowds or behind hills. We demonstrate the utility of this approach on mobile robots and in simulation for a variety of scenarios including pursuit-evasion and tag on terrains, in multi-level buildings, and in crowds. © 2011 IEEE.

Cyclic Matching Pursuits with Multiscale Time-frequency Dictionaries

DEFF Research Database (Denmark)

Sturm, Bob L.; Christensen, Mads Græsbøll

2010-01-01

We generalize cyclic matching pursuit (CMP), propose an orthogonal variant, and examine their performance using multiscale time-frequency dictionaries in the sparse approximation of signals. Overall, we find that the cyclic approach of CMP produces signal models that have a much lower approximation...

A Model of the Smooth Pursuit Eye Movement with Prediction and Learning

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Davide Zambrano

2010-01-01

Full Text Available Smooth pursuit is one of the five main eye movements in humans, consisting of tracking a steadily moving visual target. Smooth pursuit is a good example of a sensory-motor task that is deeply based on prediction: tracking a visual target is not possible by correcting the error between the eye and the target position or velocity with a feedback loop, but it is only possible by predicting the trajectory of the target. This paper presents a model of smooth pursuit based on prediction and learning. It starts from amodel of the neuro-physiological system proposed by Shibata and Schaal (Shibata et al., Neural Networks, vol. 18, pp. 213-224, 2005. The learning component added here decreases the prediction time in the case of target dynamics already experienced by the system. In the implementation described here, the convergence time is, after the learning phase, 0.8 s.

Visual sensitivity for luminance and chromatic stimuli during the execution of smooth pursuit and saccadic eye movements.

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Braun, Doris I; Schütz, Alexander C; Gegenfurtner, Karl R

2017-07-01

Visual sensitivity is dynamically modulated by eye movements. During saccadic eye movements, sensitivity is reduced selectively for low-spatial frequency luminance stimuli and largely unaffected for high-spatial frequency luminance and chromatic stimuli (Nature 371 (1994), 511-513). During smooth pursuit eye movements, sensitivity for low-spatial frequency luminance stimuli is moderately reduced while sensitivity for chromatic and high-spatial frequency luminance stimuli is even increased (Nature Neuroscience, 11 (2008), 1211-1216). Since these effects are at least partly of different polarity, we investigated the combined effects of saccades and smooth pursuit on visual sensitivity. For the time course of chromatic sensitivity, we found that detection rates increased slightly around pursuit onset. During saccades to static and moving targets, detection rates dropped briefly before the saccade and reached a minimum at saccade onset. This reduction of chromatic sensitivity was present whenever a saccade was executed and it was not modified by subsequent pursuit. We also measured contrast sensitivity for flashed high- and low-spatial frequency luminance and chromatic stimuli during saccades and pursuit. During saccades, the reduction of contrast sensitivity was strongest for low-spatial frequency luminance stimuli (about 90%). However, a significant reduction was also present for chromatic stimuli (about 58%). Chromatic sensitivity was increased during smooth pursuit (about 12%). These results suggest that the modulation of visual sensitivity during saccades and smooth pursuit is more complex than previously assumed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sparsely-Packetized Predictive Control by Orthogonal Matching Pursuit

DEFF Research Database (Denmark)

Nagahara, Masaaki; Quevedo, Daniel; Østergaard, Jan

2012-01-01

We study packetized predictive control, known to be robust against packet dropouts in networked systems. To obtain sparse packets for rate-limited networks, we design control packets via an ℓ0 optimization, which can be eectively solved by orthogonal matching pursuit. Our formulation ensures...

Narcissism and the Pursuit of Status.

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Zeigler-Hill, Virgil; Vrabel, Jennifer K; McCabe, Gillian A; Cosby, Cheryl A; Traeder, Caitlin K; Hobbs, Kelsey A; Southard, Ashton C

2018-04-10

The purpose of the present studies was to examine the connections that narcissistic admiration and narcissistic rivalry had with various aspects of status. Study 1 examined the associations that narcissism had with the motivation to seek status in a sample of 1,219 community members. Study 2 examined whether narcissism interacted with the status seeking motive to predict how individuals pursued status in a sample of 760 community members and college students. Study 3 used a daily diary approach to examine whether narcissism moderated the associations that daily perceptions of status and affiliation had with state self-esteem in 356 college students. Our results revealed that narcissistic admiration and narcissistic rivalry were somewhat similar in their desire for status but had divergent associations with other aspects of status (e.g., strategies employed to attain status, perceptions of status, reactions to perceived status). The results of the present studies suggest that narcissistic admiration is associated with an agentic orientation to the pursuit of status, whereas narcissistic rivalry is associated with an antagonistic orientation to the pursuit of status. Discussion focuses on the implications of these results for our understanding of the connections between narcissism and status. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Reframing our pursuit of life balance.

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Fuentes, David G; Ogden, Rachel R; Ryan-Haddad, Ann; Strang, Aimee F

2015-04-25

During our time in the 2013 Academic Leadership Fellows Program, we explored what it takes to achieve life balance through a framework presented in a Harvard Business Review article. In this Statement, we describe 5 different areas from the article that provide infrastructure for reflecting on how we have learned to approach life balance in academia. We also provide brief messages based on this reading and others to help academics' pursuit of life balance.

Reframing Our Pursuit of Life Balance

OpenAIRE

Fuentes, David G.; Ogden, Rachel R.; Ryan-Haddad, Ann; Strang, Aimee F.

2015-01-01

During our time in the 2013 Academic Leadership Fellows Program, we explored what it takes to achieve life balance through a framework presented in a Harvard Business Review article. In this Statement, we describe 5 different areas from the article that provide infrastructure for reflecting on how we have learned to approach life balance in academia. We also provide brief messages based on this reading and others to help academics’ pursuit of life balance.

Fast and Epsilon-Optimal Discretized Pursuit Learning Automata.

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Zhang, JunQi; Wang, Cheng; Zhou, MengChu

2015-10-01

Learning automata (LA) are powerful tools for reinforcement learning. A discretized pursuit LA is the most popular one among them. During an iteration its operation consists of three basic phases: 1) selecting the next action; 2) finding the optimal estimated action; and 3) updating the state probability. However, when the number of actions is large, the learning becomes extremely slow because there are too many updates to be made at each iteration. The increased updates are mostly from phases 1 and 3. A new fast discretized pursuit LA with assured ε -optimality is proposed to perform both phases 1 and 3 with the computational complexity independent of the number of actions. Apart from its low computational complexity, it achieves faster convergence speed than the classical one when operating in stationary environments. This paper can promote the applications of LA toward the large-scale-action oriented area that requires efficient reinforcement learning tools with assured ε -optimality, fast convergence speed, and low computational complexity for each iteration.

Hybrid Video Coding Based on Bidimensional Matching Pursuit

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Lorenzo Granai

2004-12-01

Full Text Available Hybrid video coding combines together two stages: first, motion estimation and compensation predict each frame from the neighboring frames, then the prediction error is coded, reducing the correlation in the spatial domain. In this work, we focus on the latter stage, presenting a scheme that profits from some of the features introduced by the standard H.264/AVC for motion estimation and replaces the transform in the spatial domain. The prediction error is so coded using the matching pursuit algorithm which decomposes the signal over an appositely designed bidimensional, anisotropic, redundant dictionary. Comparisons are made among the proposed technique, H.264, and a DCT-based coding scheme. Moreover, we introduce fast techniques for atom selection, which exploit the spatial localization of the atoms. An adaptive coding scheme aimed at optimizing the resource allocation is also presented, together with a rate-distortion study for the matching pursuit algorithm. Results show that the proposed scheme outperforms the standard DCT, especially at very low bit rates.

The Role of Dopamine in Anticipatory Pursuit Eye Movements: Insights from Genetic Polymorphisms in Healthy Adults.

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Billino, Jutta; Hennig, Jürgen; Gegenfurtner, Karl R

2016-01-01

There is a long history of eye movement research in patients with psychiatric diseases for which dysfunctions of neurotransmission are considered to be the major pathologic mechanism. However, neuromodulation of oculomotor control is still hardly understood. We aimed to investigate in particular the impact of dopamine on smooth pursuit eye movements. Systematic variability in dopaminergic transmission due to genetic polymorphisms in healthy subjects offers a noninvasive opportunity to determine functional associations. We measured smooth pursuit in 110 healthy subjects genotyped for two well-documented polymorphisms, the COMT Val 158 Met polymorphism and the SLC6A3 3'-UTR-VNTR polymorphism. Pursuit paradigms were chosen to particularly assess the ability of the pursuit system to initiate tracking when target motion onset is blanked, reflecting the impact of extraretinal signals. In contrast, when following a fully visible target sensory, retinal signals are available. Our results highlight the crucial functional role of dopamine for anticipatory, but not for sensory-driven, pursuit processes. We found the COMT Val 158 Met polymorphism specifically associated with anticipatory pursuit parameters, emphasizing the dominant impact of prefrontal dopamine activity on complex oculomotor control. In contrast, modulation of striatal dopamine activity by the SLC6A3 3'-UTR-VNTR polymorphism had no significant functional effect. Though often neglected so far, individual differences in healthy subjects provide a promising approach to uncovering functional mechanisms and can be used as a bridge to understanding deficits in patients.

Comparison of l₁-Norm SVR and Sparse Coding Algorithms for Linear Regression.

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Zhang, Qingtian; Hu, Xiaolin; Zhang, Bo

2015-08-01

Support vector regression (SVR) is a popular function estimation technique based on Vapnik's concept of support vector machine. Among many variants, the l1-norm SVR is known to be good at selecting useful features when the features are redundant. Sparse coding (SC) is a technique widely used in many areas and a number of efficient algorithms are available. Both l1-norm SVR and SC can be used for linear regression. In this brief, the close connection between the l1-norm SVR and SC is revealed and some typical algorithms are compared for linear regression. The results show that the SC algorithms outperform the Newton linear programming algorithm, an efficient l1-norm SVR algorithm, in efficiency. The algorithms are then used to design the radial basis function (RBF) neural networks. Experiments on some benchmark data sets demonstrate the high efficiency of the SC algorithms. In particular, one of the SC algorithms, the orthogonal matching pursuit is two orders of magnitude faster than a well-known RBF network designing algorithm, the orthogonal least squares algorithm.

Responses of Purkinje cells in the oculomotor vermis of monkeys during smooth pursuit eye movements and saccades: comparison with floccular complex.

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Raghavan, Ramanujan T; Lisberger, Stephen G

2017-08-01

We recorded the responses of Purkinje cells in the oculomotor vermis during smooth pursuit and saccadic eye movements. Our goal was to characterize the responses in the vermis using approaches that would allow direct comparisons with responses of Purkinje cells in another cerebellar area for pursuit, the floccular complex. Simple-spike firing of vermis Purkinje cells is direction selective during both pursuit and saccades, but the preferred directions are sufficiently independent so that downstream circuits could decode signals to drive pursuit and saccades separately. Complex spikes also were direction selective during pursuit, and almost all Purkinje cells showed a peak in the probability of complex spikes during the initiation of pursuit in at least one direction. Unlike the floccular complex, the preferred directions for simple spikes and complex spikes were not opposite. The kinematics of smooth eye movement described the simple-spike responses of vermis Purkinje cells well. Sensitivities were similar to those in the floccular complex for eye position and considerably lower for eye velocity and acceleration. The kinematic relations were quite different for saccades vs. pursuit, supporting the idea that the contributions from the vermis to each kind of movement could contribute independently in downstream areas. Finally, neither the complex-spike nor the simple-spike responses of vermis Purkinje cells were appropriate to support direction learning in pursuit. Complex spikes were not triggered reliably by an instructive change in target direction; simple-spike responses showed very small amounts of learning. We conclude that the vermis plays a different role in pursuit eye movements compared with the floccular complex. NEW & NOTEWORTHY The midline oculomotor cerebellum plays a different role in smooth pursuit eye movements compared with the lateral, floccular complex and appears to be much less involved in direction learning in pursuit. The output from the

Goal pursuit, goal adjustment, and affective well-being following lower limb amputation.

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Coffey, Laura; Gallagher, Pamela; Desmond, Deirdre; Ryall, Nicola

2014-05-01

This study examined the relationships between tenacious goal pursuit (TGP), flexible goal adjustment (FGA), and affective well-being in a sample of individuals with lower limb amputations. Cross-sectional, quantitative. Ninety-eight patients recently admitted to a primary prosthetic rehabilitation programme completed measures of TGP, FGA, positive affect, and negative affect. Hierarchical regression analyses revealed that TGP and FGA accounted for a significant proportion of the variance in both positive and negative affect, controlling for sociodemographic and clinical characteristics. TGP was significantly positively associated with positive affect, while FGA was significantly negatively associated with negative affect. Moderated regression analyses indicated that the beneficial effect of FGA on negative affect was strongest at high levels of amputation-related pain intensity and low levels of TGP. TGP and FGA appear to influence subjective well-being in different ways, with TGP promoting the experience of positive affect and FGA buffering against negative affect. TGP and FGA may prove useful in identifying individuals at risk of poor affective outcomes following lower limb amputation and represent important targets for intervention in this patient group. What is already known on this subject? The loss of a limb has a significant impact on several important life domains. Although some individuals experience emotional distress following amputation, the majority adjust well to their limb loss, with some achieving positive change or growth as a result of their experiences. Theories of self-regulation propose that disruptions in goal attainment have negative affective consequences. The physical, social, and psychological upheaval caused by limb loss is likely to threaten the attainment of valued goals, which may leave individuals vulnerable to negative psychosocial outcomes if they do not regulate their goals in response to these challenges. According to the dual

Comparison of two-concentration with multi-concentration linear regressions: Retrospective data analysis of multiple regulated LC-MS bioanalytical projects.

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Musuku, Adrien; Tan, Aimin; Awaiye, Kayode; Trabelsi, Fethi

2013-09-01

Linear calibration is usually performed using eight to ten calibration concentration levels in regulated LC-MS bioanalysis because a minimum of six are specified in regulatory guidelines. However, we have previously reported that two-concentration linear calibration is as reliable as or even better than using multiple concentrations. The purpose of this research is to compare two-concentration with multiple-concentration linear calibration through retrospective data analysis of multiple bioanalytical projects that were conducted in an independent regulated bioanalytical laboratory. A total of 12 bioanalytical projects were randomly selected: two validations and two studies for each of the three most commonly used types of sample extraction methods (protein precipitation, liquid-liquid extraction, solid-phase extraction). When the existing data were retrospectively linearly regressed using only the lowest and the highest concentration levels, no extra batch failure/QC rejection was observed and the differences in accuracy and precision between the original multi-concentration regression and the new two-concentration linear regression are negligible. Specifically, the differences in overall mean apparent bias (square root of mean individual bias squares) are within the ranges of -0.3% to 0.7% and 0.1-0.7% for the validations and studies, respectively. The differences in mean QC concentrations are within the ranges of -0.6% to 1.8% and -0.8% to 2.5% for the validations and studies, respectively. The differences in %CV are within the ranges of -0.7% to 0.9% and -0.3% to 0.6% for the validations and studies, respectively. The average differences in study sample concentrations are within the range of -0.8% to 2.3%. With two-concentration linear regression, an average of 13% of time and cost could have been saved for each batch together with 53% of saving in the lead-in for each project (the preparation of working standard solutions, spiking, and aliquoting). Furthermore

Incremental principal component pursuit for video background modeling

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Rodriquez-Valderrama, Paul A.; Wohlberg, Brendt

2017-03-14

An incremental Principal Component Pursuit (PCP) algorithm for video background modeling that is able to process one frame at a time while adapting to changes in background, with a computational complexity that allows for real-time processing, having a low memory footprint and is robust to translational and rotational jitter.

The Influence of Money on Goal Pursuit and Decision-Making: Understanding Money's Unique Impact on Goal Pursuit

OpenAIRE

Moran, Nora

2015-01-01

Previous research suggests that activating concepts of money and wealth can increase motivation to achieve personal goals. In this dissertation, I investigate how money affects pursuit of important personal goals, and how this motivation may be affected by goal attainability. In eight studies, I show that priming concepts of money and wealth leads individuals to pursue important personal goals to a greater degree than control groups, but only when a goal is more attainable. In contrast, when...

Perceptual learning modifies untrained pursuit eye movements

OpenAIRE

Szpiro, Sarit F. A.; Spering, Miriam; Carrasco, Marisa

2014-01-01

Perceptual learning improves detection and discrimination of relevant visual information in mature humans, revealing sensory plasticity. Whether visual perceptual learning affects motor responses is unknown. Here we implemented a protocol that enabled us to address this question. We tested a perceptual response (motion direction estimation, in which observers overestimate motion direction away from a reference) and a motor response (voluntary smooth pursuit eye movements). Perceptual training...

Extrinsic relative to intrinsic goal pursuits and peer dynamics: selection and influence processes among adolescents.

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Duriez, Bart; Giletta, Matteo; Kuppens, Peter; Vansteenkiste, Maarten

2013-10-01

Self-Determination Theory discerns goals and values in terms of whether they are intrinsic or extrinsic in nature. Although research substantiates the importance of goal preferences for a host of outcomes, few studies examined how such preferences develop, and studies that did pay attention to this focused on parental influence processes. The present study focuses on the role of peers. Social network analyses on longitudinal data gathered among senior high-school students (N = 695) confirm that peer similarity in goal pursuit exists, and that, although this similarity partly originates from adolescents selecting friends on the basis of perceived goal pursuit similarity, it also results from peers actively influencing each other. Hence, friends tend to become more alike in terms of goal pursuit over time. Data also suggest that, although changes in goal pursuit at this age can be predicted from peer dynamics, they cannot be attributed to parental goal promotion efforts. Copyright © 2013 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

The unconscious and conscious foundations of human reward pursuit

NARCIS (Netherlands)

Bijleveld, E.|info:eu-repo/dai/nl/313905223

2012-01-01

Human reward pursuit is often found to be governed by conscious assessments of expected value and required effort. Yet, research also indicates that rewards are initially valuated and processed outside awareness, using rudimentary brain structures. Building on both findings, a new framework is

The role of self-transcendence: a missing variable in the pursuit of successful aging?

Science.gov (United States)

McCarthy, Valerie Lander; Ling, Jiying; Carini, Robert M

2013-07-01

While successful aging is often defined as the absence of disease and disability or as life satisfaction, self-transcendence may also play an important role. The objective of this research was to test a nursing theory of successful aging proposing that transcendence and adaptation predict successful aging. In this cross-sectional exploratory study, a convenience sample of older adults (N = 152) were surveyed about self-transcendence, proactive coping, and successful aging. Using hierarchical multiple regression, self-transcendence, proactive coping, and all control variables (i.e., sex, race, perceived health, place of residence) together explained 50% of the variance in successful aging (p self-transcendence and proactive coping predict successful aging. Self-transcendence was the only significant contributor to this multidimensional view of successful aging. Self-transcendence is an important variable in the pursuit of successful aging, which merits further investigation. Copyright 2013, SLACK Incorporated.

Stable schizophrenia patients learn equally well as age-matched controls and better than elderly controls in two sensorimotor rotary pursuit tasks

NARCIS (Netherlands)

Picker, L.J. De; Cornelis, C.; Hulstijn, W.; Dumont, G.J.H.; Fransen, E.; Timmers, M.; Janssens, L.; Morrens, M.; Sabbe, B.G.C.

2014-01-01

Objective: To compare sensorimotor performance and learning in stable schizophrenia patients, healthy age- and sex-matched controls and elderly controls on two variations of the rotary pursuit: circle pursuit (true motor learning) and figure pursuit (motor and sequence learning). Method: In the

Utility-value intervention with parents increases students' STEM preparation and career pursuit.

Science.gov (United States)

Rozek, Christopher S; Svoboda, Ryan C; Harackiewicz, Judith M; Hulleman, Chris S; Hyde, Janet S

2017-01-31

During high school, developing competence in science, technology, engineering, and mathematics (STEM) is critically important as preparation to pursue STEM careers, yet students in the United States lag behind other countries, ranking 35th in mathematics and 27th in science achievement internationally. Given the importance of STEM careers as drivers of modern economies, this deficiency in preparation for STEM careers threatens the United States' continued economic progress. In the present study, we evaluated the long-term effects of a theory-based intervention designed to help parents convey the importance of mathematics and science courses to their high-school-aged children. A prior report on this intervention showed that it promoted STEM course-taking in high school; in the current follow-up study, we found that the intervention improved mathematics and science standardized test scores on a college preparatory examination (ACT) for adolescents by 12 percentile points. Greater high-school STEM preparation (STEM course-taking and ACT scores) was associated with increased STEM career pursuit (i.e., STEM career interest, the number of college STEM courses, and students' attitudes toward STEM) 5 y after the intervention. These results suggest that the intervention can affect STEM career pursuit indirectly by increasing high-school STEM preparation. This finding underscores the importance of targeting high-school STEM preparation to increase STEM career pursuit. Overall, these findings demonstrate that a motivational intervention with parents can have important effects on STEM preparation in high school, as well as downstream effects on STEM career pursuit 5 y later.

Illegitimacy Improves Goal Pursuit in Powerless Individuals

OpenAIRE

Willis , Guillermo B.; Guinote , Ana; Rodríguez-Bailón , Rosa

2009-01-01

Abstract The effects of power legitimacy on self-regulation during goal pursuit were examined. Study 1 focused on goal-setting and goal-striving. Specifically, it examined how much time legitimate and illegitimate powerless individuals needed to set goals, and how many means they generated to pursue these goals. Study 2 examined persistence in the face of difficulties. Consistently across these studies illegitimacy improved self-regulation in powerless individuals. Illegitimate pow...

Variances in the projections, resulting from CLIMEX, Boosted Regression Trees and Random Forests techniques

Science.gov (United States)

Shabani, Farzin; Kumar, Lalit; Solhjouy-fard, Samaneh

2017-08-01

The aim of this study was to have a comparative investigation and evaluation of the capabilities of correlative and mechanistic modeling processes, applied to the projection of future distributions of date palm in novel environments and to establish a method of minimizing uncertainty in the projections of differing techniques. The location of this study on a global scale is in Middle Eastern Countries. We compared the mechanistic model CLIMEX (CL) with the correlative models MaxEnt (MX), Boosted Regression Trees (BRT), and Random Forests (RF) to project current and future distributions of date palm ( Phoenix dactylifera L.). The Global Climate Model (GCM), the CSIRO-Mk3.0 (CS) using the A2 emissions scenario, was selected for making projections. Both indigenous and alien distribution data of the species were utilized in the modeling process. The common areas predicted by MX, BRT, RF, and CL from the CS GCM were extracted and compared to ascertain projection uncertainty levels of each individual technique. The common areas identified by all four modeling techniques were used to produce a map indicating suitable and unsuitable areas for date palm cultivation for Middle Eastern countries, for the present and the year 2100. The four different modeling approaches predict fairly different distributions. Projections from CL were more conservative than from MX. The BRT and RF were the most conservative methods in terms of projections for the current time. The combination of the final CL and MX projections for the present and 2100 provide higher certainty concerning those areas that will become highly suitable for future date palm cultivation. According to the four models, cold, hot, and wet stress, with differences on a regional basis, appears to be the major restrictions on future date palm distribution. The results demonstrate variances in the projections, resulting from different techniques. The assessment and interpretation of model projections requires reservations

Sense of place in outdoor-pursuits trip groups

Science.gov (United States)

Sharon L. Todd; Anderson B. Young; Lynn S. Anderson; Timothy S. O' Connell; Mary Breunig

2009-01-01

Studies have revealed that sense of community and group cohesion increase significantly over time in outdoor-pursuits trip groups. This study sought to understand similar development of sense of place. Do people simultaneously become more attached to or dependent on the natural environment as they grow closer to each other? Results from a study of college students...

[The role of job satisfaction in the person-organization fit relationship in terms of goal pursuit strategies, and mental health].

Science.gov (United States)

Roczniewska, Marta; Retowski, Sylwiusz

2014-01-01

Person-organization (P-O) fit is a predictor of job satisfaction, and a misfit is a potential stressor. We aimed to examine the consequences of fit between a person and an organization in terms of goal pursuit strategies. We tested whether job satisfaction mediates the relationship between regulatory fit and mental health. Research was conducted in a group of 169 employees. They were asked to fill in questionnaires assessing their chronic work regulatory focus, organiza tional regulatory focus and job satisfaction. To measure mental well-being we administered the General Health Questionnaire (GHQ-28). We conducted mediation analysis in regression. The results of the mediation analysis confirmed the me- diating role of job satisfaction in the relation between regulatory focus misfit and physical and mental symptoms of distress. The results of this study point to the fact that P-O fit can relate to goal pursuit strategies. It influences not only job satisfaction, but also employees' health.The conclusions can be applied in the human resources management practices, e.g., it may serve as a useful argument to motivate employers to shape goals and strategies individually by managers, according to employees preferences. The results should be interpreted with caution because of non-random sampling.

Regression Benchmarking: An Approach to Quality Assurance in Performance

OpenAIRE

Bulej, Lubomír

2005-01-01

The paper presents a short summary of our work in the area of regression benchmarking and its application to software development. Specially, we explain the concept of regression benchmarking, the requirements for employing regression testing in a software project, and methods used for analyzing the vast amounts of data resulting from repeated benchmarking. We present the application of regression benchmarking on a real software project and conclude with a glimpse at the challenges for the fu...

The relationship between implicit and explicit motives, goal pursuit, and autobiographical memory content during a diary study

NARCIS (Netherlands)

Bender, M.; Woike, B.A.; Burke, C.; Dow, E.A.A.

2012-01-01

This online diary study investigated how motives interact with goal pursuit to predict daily autobiographical experiences. Participants (N = 141) completed measures of implicit and explicit achievement, provided daily memories and reports of their goal pursuit during a 3-week diary period. A

SmoothMoves : Smooth pursuits head movements for augmented reality

NARCIS (Netherlands)

Esteves, Augusto; Verweij, David; Suraiya, Liza; Islam, Rasel; Lee, Youryang; Oakley, Ian

2017-01-01

SmoothMoves is an interaction technique for augmented reality (AR) based on smooth pursuits head movements. It works by computing correlations between the movements of on-screen targets and the user's head while tracking those targets. The paper presents three studies. The first suggests that head

Narcissism and the Strategic Pursuit of Short-Term Mating: Universal Links across 11 World Regions of the International Sexuality Description Project-2

OpenAIRE

Schmitt, David P.; Alcalay, Lidia; Allik, Jüri; Alves, I. C. B.; Anderson, Craig A.; Angelini, A. L.; Asendorpf, Jens B.; Austers, Ivars; Balaguer, Isabel; Baptista, Américo; Bender, Sóley S.; Bennett, Kevin; Bianchi, Gabriel; Bianchi, Behrooz; Bleske-Rechek, April

2017-01-01

Previous studies have documented links between sub-clinical narcissism and the active pursuit of short-term mating strategies (e.g., unrestricted sociosexuality, marital infidelity, mate poaching). Nearly all of these investigations have relied solely on samples from Western cultures. In the current study, responses from a cross-cultural survey of 30,470 people across 53 nations spanning 11 world regions (North America, Central/South America, Northern Europe, Western Europe, Eastern Europe, S...

Narcissism and the strategic pursuit of short-term mating : universal links across 11 world regions of the International Sexuality Description Project-2.

OpenAIRE

Schmitt, David; Alcalay, Lidia; Allik, Jüri; Alves, I.C.B.; Anderson, Craig; Angelini, A.L.; Asendorpf, Jens; Austers, Ivars; Balaguer, Isabel; Baptista, Américo; Bender, Sóley; Bennett, Kevin; Bianchi, Gabriel; Birashk, Behrooz; Bleske, April

2017-01-01

Previous studies have documented links between sub-clinical narcissism and the active pursuit of short-term mating strategies (e.g., unrestricted sociosexuality, marital infidelity, mate poaching). Nearly all of these investigations have relied solely on samples from Western cultures. In the current study, responses from a cross-cultural survey of 30,470 people across 53 nations spanning 11 world regions (North America, Central/South America, Northern Europe, Western Europe, Eastern Europe, S...

Landmine detection using two-tapped joint orthogonal matching pursuits

Science.gov (United States)

Goldberg, Sean; Glenn, Taylor; Wilson, Joseph N.; Gader, Paul D.

2012-06-01

Joint Orthogonal Matching Pursuits (JOMP) is used here in the context of landmine detection using data obtained from an electromagnetic induction (EMI) sensor. The response from an object containing metal can be decomposed into a discrete spectrum of relaxation frequencies (DSRF) from which we construct a dictionary. A greedy iterative algorithm is proposed for computing successive residuals of a signal by subtracting away the highest matching dictionary element at each step. The nal condence of a particular signal is a combination of the reciprocal of this residual and the mean of the complex component. A two-tap approach comparing signals on opposite sides of the geometric location of the sensor is examined and found to produce better classication. It is found that using only a single pursuit does a comparable job, reducing complexity and allowing for real-time implementation in automated target recognition systems. JOMP is particularly highlighted in comparison with a previous EMI detection algorithm known as String Match.

Toward Simulating Realistic Pursuit-Evasion Using a Roadmap-Based Approach

KAUST Repository

Rodriguez, Samuel; Denny, Jory; Zourntos, Takis; Amato, Nancy M.

2010-01-01

In this work, we describe an approach for modeling and simulating group behaviors for pursuit-evasion that uses a graph-based representation of the environment and integrates multi-agent simulation with roadmap-based path planning. We demonstrate

Sharpen customer service skills with PCRAFT Pursuit.

Science.gov (United States)

Dologite, Kimberly A; Willner, Kathleen C; Klepeiss, Debra J; York, Susan A; Cericola, Lisa M

2003-01-01

Traditional approaches to teaching customer service skills do not involve participant interaction, nor do they provide a fun and relaxed atmosphere for learning. This article describes the development of PCRAFT Pursuit, an innovative game used to teach customer service skills. The development process began with concerns identified through patient satisfaction surveys. The implementation of this game became an integral component of education to improve customer service skills of staff throughout the hospital network.

Dissecting patterns of preparatory activity in the frontal eye fields during pursuit target selection.

Science.gov (United States)

Raghavan, Ramanujan T; Joshua, Mati

2017-10-01

We investigated the composition of preparatory activity of frontal eye field (FEF) neurons in monkeys performing a pursuit target selection task. In response to the orthogonal motion of a large and a small reward target, monkeys initiated pursuit biased toward the direction of large reward target motion. FEF neurons exhibited robust preparatory activity preceding movement initiation in this task. Preparatory activity consisted of two components, ramping activity that was constant across target selection conditions, and a flat offset in firing rates that signaled the target selection condition. Ramping activity accounted for 50% of the variance in the preparatory activity and was linked most strongly, on a trial-by-trial basis, to pursuit eye movement latency rather than to its direction or gain. The offset in firing rates that discriminated target selection conditions accounted for 25% of the variance in the preparatory activity and was commensurate with a winner-take-all representation, signaling the direction of large reward target motion rather than a representation that matched the parameters of the upcoming movement. These offer new insights into the role that the frontal eye fields play in target selection and pursuit control. They show that preparatory activity in the FEF signals more strongly when to move rather than where or how to move and suggest that structures outside the FEF augment its contributions to the target selection process. NEW & NOTEWORTHY We used the smooth eye movement pursuit system to link between patterns of preparatory activity in the frontal eye fields and movement during a target selection task. The dominant pattern was a ramping signal that did not discriminate between selection conditions and was linked, on trial-by-trial basis, to movement latency. A weaker pattern was composed of a constant signal that discriminated between selection conditions but was only weakly linked to the movement parameters. Copyright © 2017 the American

Value, What Value? University Business Model in Pursuit of Advanced Internationalization

DEFF Research Database (Denmark)

Juho, Anita; Turcan, Romeo V.

Through business model theoretical lenses, we explore in this paper issues and challenges universities face in their pursuit of advanced internationalization entries into foreign markets. The context of this paper is defined by universities from developed countries entering developing or emerging...... countries via foreign direct investment entry modes, such as joint ventures, acquisitions, green field or brown field investments. This is a theoretical paper. We draw on a number of sources of data to conceptualise issues and challenges universities face in their pursuit of advanced internationalization...... entries into foreign markets. First, we build on university autonomy, international business and business model theories to conceptualise the phenomenon of interest. Second, we analyse publicly available data, anecdotal evidence where the phenomenon we study is explicitly observable. The above theoretical...

The benefits of interpersonal regulatory fit for individual goal pursuit.

NARCIS (Netherlands)

Righetti, F.; Finkenauer, C.; Rusbult, C. E.

2011-01-01

The present work examines whether individual goal pursuit is influenced by advice and suggestions from interaction partners whose regulatory orientation is perceived to fit (vs. not fit) the individual's orientation. We sought to investigate whether such interpersonal regulatory fit yields

Reduction of snapshots for MIMO radar detection by block/group orthogonal matching pursuit

KAUST Repository

Ali, Hussain El Hosiny

2014-10-01

Multiple-input multiple-output (MIMO) radar works on the principle of transmission of independent waveforms at each element of its antenna array and is widely used for surveillance purposes. In this work, we investigate MIMO radar target localization problem with compressive sensing. Specifically, we try to solve the problem of estimation of target location in MIMO radar by group and block sparsity algorithms. It will lead us to a reduced number of snapshots required and also we can achieve better radar resolution. We will use group orthogonal matching pursuit (GOMP) and block orthogonal matching pursuit (BOMP) for our problem. © 2014 IEEE.

Trait motivation moderates neural activation associated with goal pursuit.

Science.gov (United States)

Spielberg, Jeffrey M; Miller, Gregory A; Warren, Stacie L; Engels, Anna S; Crocker, Laura D; Sutton, Bradley P; Heller, Wendy

2012-06-01

Research has indicated that regions of left and right dorsolateral prefrontal cortex (DLPFC) are involved in integrating the motivational and executive function processes related to, respectively, approach and avoidance goals. Given that sensitivity to pleasant and unpleasant stimuli is an important feature of conceptualizations of approach and avoidance motivation, it is possible that these regions of DLPFC are preferentially activated by valenced stimuli. The present study tested this hypothesis by using a task in which goal pursuit was threatened by distraction from valenced stimuli while functional magnetic resonance imaging data were collected. The analyses examined whether the impact of trait approach and avoidance motivation on the neural processes associated with executive function differed depending on the valence or arousal level of the distractor stimuli. The present findings support the hypothesis that the regions of DLPFC under investigation are involved in integrating motivational and executive function processes, and they also indicate the involvement of a number of other brain areas in maintaining goal pursuit. However, DLPFC did not display differential sensitivity to valence.

Exercise participation and diet monitoring in pursuit of healthy aging ...

African Journals Online (AJOL)

This study examined the level of exercise participation and diet monitoring in pursuit of healthy aging. Descriptive survey research design and self-structured questionnaire was used to elicit information from the respondents. Proportionate stratified and simple random sampling techniques were used to select two hundred ...

Do we track what we see? Common versus independent processing for motion perception and smooth pursuit eye movements: a review.

Science.gov (United States)

Spering, Miriam; Montagnini, Anna

2011-04-22

Many neurophysiological studies in monkeys have indicated that visual motion information for the guidance of perception and smooth pursuit eye movements is - at an early stage - processed in the same visual pathway in the brain, crucially involving the middle temporal area (MT). However, these studies left some questions unanswered: Are perception and pursuit driven by the same or independent neuronal signals within this pathway? Are the perceptual interpretation of visual motion information and the motor response to visual signals limited by the same source of neuronal noise? Here, we review psychophysical studies that were motivated by these questions and compared perception and pursuit behaviorally in healthy human observers. We further review studies that focused on the interaction between perception and pursuit. The majority of results point to similarities between perception and pursuit, but dissociations were also reported. We discuss recent developments in this research area and conclude with suggestions for common and separate principles for the guidance of perceptual and motor responses to visual motion information. Copyright © 2010 Elsevier Ltd. All rights reserved.

Stable schizophrenia patients learn equally well as age-matched controls and better than elderly controls in two sensorimotor Rotary Pursuit tasks

Directory of Open Access Journals (Sweden)

Livia J. De Picker

2014-11-01

Full Text Available Objective: To compare sensorimotor performance and learning in stable schizophrenia patients, healthy age- and sex-matched controls and elderly controls on two variations of the Rotary Pursuit: Circle Pursuit (true motor learning and Figure Pursuit (motor and sequence learning.Method: In the Circle Pursuit a target circle, rotating with increasing speed along a predictable circular path on the computer screen, must be followed by a cursor controlled by a pen on a writing tablet. In the eight-trial Figure Pursuit, subjects learn to draw a complex figure by pursuing the target circle that moves along an invisible trajectory between and around several goals. Tasks were administered thrice (day 1, day 2, day 7 to 30 patients with stable schizophrenia (S, 30 healthy age- and sex-matched controls (C and 30 elderly participants (>65y; E and recorded with a digitizing tablet and pressure-sensitive pen. The outcome measure accuracy (% of time that cursor is within the target was used to assess performance.Results: We observed significant group differences in accuracy, both in Circle and Figure Pursuit tasks (EPursuit but differed between groups in Figure Pursuit. When corrected for group differences in starting level, the learning gains over the three sessions of schizophrenia patients and age-matched controls were equal and both were larger than those of the elderly controls. Conclusion: Despite the reduced sensorimotor performance that was found in the schizophrenia patients their sensorimotor learning seems to be preserved. The relevance of this finding for the evaluation of procedural learning in schizophrenia is discussed. The better performance and learning rate of the patients compared to the elderly controls was unexpected and deserves further study.

Matching-pursuit/split-operator Fourier-transform simulations of nonadiabatic quantum dynamics

Science.gov (United States)

Wu, Yinghua; Herman, Michael F.; Batista, Victor S.

2005-03-01

A rigorous and practical approach for simulations of nonadiabatic quantum dynamics is introduced. The algorithm involves a natural extension of the matching-pursuit/split-operator Fourier-transform (MP/SOFT) method [Y. Wu and V. S. Batista, J. Chem. Phys. 121, 1676 (2004)] recently developed for simulations of adiabatic quantum dynamics in multidimensional systems. The MP/SOFT propagation scheme, extended to nonadiabatic dynamics, recursively applies the time-evolution operator as defined by the standard perturbation expansion to first-, or second-order, accuracy. The expansion is implemented in dynamically adaptive coherent-state representations, generated by an approach that combines the matching-pursuit algorithm with a gradient-based optimization method. The accuracy and efficiency of the resulting propagation method are demonstrated as applied to the canonical model systems introduced by Tully for testing simulations of dual curve-crossing nonadiabatic dynamics.

How Do Interaction Experiences Influence Doctoral Students’ Academic Pursuits in Biomedical Research?

Science.gov (United States)

Kong, Xiaoqing; Chakraverty, Devasmita; Jeffe, Donna B.; Andriole, Dorothy A.; Wathington, Heather D.; Tai, Robert H.

2014-01-01

This exploratory qualitative study investigated how doctoral students reported their personal and professional interaction experiences that they believed might facilitate or impede their academic pursuits in biomedical research. We collected 19 in-depth interviews with doctoral students in biomedical research from eight universities, and we based our qualitative analytic approach on the work of Miles and Huberman. The results indicated that among different sources and types of interaction, academic and emotional interactions from family and teachers in various stages essentially affected students’ persistence in the biomedical science field. In addition, co-mentorship among peers, departmental environment, and volunteer experiences were other essential factors. This study also found related experiences among women and underrepresented minority students that were important to their academic pursuit. PMID:26166928

How Do Interaction Experiences Influence Doctoral Students' Academic Pursuits in Biomedical Research?

Science.gov (United States)

Kong, Xiaoqing; Chakraverty, Devasmita; Jeffe, Donna B; Andriole, Dorothy A; Wathington, Heather D; Tai, Robert H

2013-01-01

This exploratory qualitative study investigated how doctoral students reported their personal and professional interaction experiences that they believed might facilitate or impede their academic pursuits in biomedical research. We collected 19 in-depth interviews with doctoral students in biomedical research from eight universities, and we based our qualitative analytic approach on the work of Miles and Huberman. The results indicated that among different sources and types of interaction, academic and emotional interactions from family and teachers in various stages essentially affected students' persistence in the biomedical science field. In addition, co-mentorship among peers, departmental environment, and volunteer experiences were other essential factors. This study also found related experiences among women and underrepresented minority students that were important to their academic pursuit.

Independent histogram pursuit for segmentation of skin lesions

DEFF Research Database (Denmark)

Gomez, D.D.; Butakoff, C.; Ersbøll, Bjarne Kjær

2008-01-01

In this paper, an unsupervised algorithm, called the Independent Histogram Pursuit (HIP), for segmenting dermatological lesions is proposed. The algorithm estimates a set of linear combinations of image bands that enhance different structures embedded in the image. In particular, the first estima...... to deal with different types of dermatological lesions. The boundary detection precision using k-means segmentation was close to 97%. The proposed algorithm can be easily combined with the majority of classification algorithms....

Pursuit of excellence: A forgotten quest?

Directory of Open Access Journals (Sweden)

Mark B Wertheimer

2018-01-01

Full Text Available The article explores the current orthodontic landscape with respect to the challenges that affect the pursuit of excellence in the specialty. These challenges include marketing by manufacturing companies, financial pressures, marketplace competition, attaining practice efficiency, new product introduction with limited supporting evidence, attributing greater importance to patient experience than the best approach to treatment, and lack of public education regarding their best interests. Home or DIY treatment, bypassing office visits and the practitioner, have also emerged as a concerning trend with the public not clearly understanding the detrimental consequences that may ensue. An over reliance on technology may override individualized treatment and further compromise treatment results.

When hawks attack: animal-borne video studies of goshawk pursuit and prey-evasion strategies

Science.gov (United States)

Kane, Suzanne Amador; Fulton, Andrew H.; Rosenthal, Lee J.

2015-01-01

Video filmed by a camera mounted on the head of a Northern Goshawk (Accipiter gentilis) was used to study how the raptor used visual guidance to pursue prey and land on perches. A combination of novel image analysis methods and numerical simulations of mathematical pursuit models was used to determine the goshawk's pursuit strategy. The goshawk flew to intercept targets by fixing the prey at a constant visual angle, using classical pursuit for stationary prey, lures or perches, and usually using constant absolute target direction (CATD) for moving prey. Visual fixation was better maintained along the horizontal than vertical direction. In some cases, we observed oscillations in the visual fix on the prey, suggesting that the goshawk used finite-feedback steering. Video filmed from the ground gave similar results. In most cases, it showed goshawks intercepting prey using a trajectory consistent with CATD, then turning rapidly to attack by classical pursuit; in a few cases, it showed them using curving non-CATD trajectories. Analysis of the prey's evasive tactics indicated that only sharp sideways turns caused the goshawk to lose visual fixation on the prey, supporting a sensory basis for the surprising frequency and effectiveness of this tactic found by previous studies. The dynamics of the prey's looming image also suggested that the goshawk used a tau-based interception strategy. We interpret these results in the context of a concise review of pursuit–evasion in biology, and conjecture that some prey deimatic ‘startle’ displays may exploit tau-based interception. PMID:25609783

Local bilinear multiple-output quantile/depth regression

Czech Academy of Sciences Publication Activity Database

Hallin, M.; Lu, Z.; Paindaveine, D.; Šiman, Miroslav

2015-01-01

Roč. 21, č. 3 (2015), s. 1435-1466 ISSN 1350-7265 R&D Projects: GA MŠk(CZ) 1M06047 Institutional support: RVO:67985556 Keywords : conditional depth * growth chart * halfspace depth * local bilinear regression * multivariate quantile * quantile regression * regression depth Subject RIV: BA - General Mathematics Impact factor: 1.372, year: 2015 http://library.utia.cas.cz/separaty/2015/SI/siman-0446857.pdf

Methodology for the AutoRegressive Planet Search (ARPS) Project

Science.gov (United States)

Feigelson, Eric; Caceres, Gabriel; ARPS Collaboration

2018-01-01

The detection of periodic signals of transiting exoplanets is often impeded by the presence of aperiodic photometric variations. This variability is intrinsic to the host star in space-based observations (typically arising from magnetic activity) and from observational conditions in ground-based observations. The most common statistical procedures to remove stellar variations are nonparametric, such as wavelet decomposition or Gaussian Processes regression. However, many stars display variability with autoregressive properties, wherein later flux values are correlated with previous ones. Providing the time series is evenly spaced, parametric autoregressive models can prove very effective. Here we present the methodology of the Autoregessive Planet Search (ARPS) project which uses Autoregressive Integrated Moving Average (ARIMA) models to treat a wide variety of stochastic short-memory processes, as well as nonstationarity. Additionally, we introduce a planet-search algorithm to detect periodic transits in the time-series residuals after application of ARIMA models. Our matched-filter algorithm, the Transit Comb Filter (TCF), replaces the traditional box-fitting step. We construct a periodogram based on the TCF to concentrate the signal of these periodic spikes. Various features of the original light curves, the ARIMA fits, the TCF periodograms, and folded light curves at peaks of the TCF periodogram can then be collected to provide constraints for planet detection. These features provide input into a multivariate classifier when a training set is available. The ARPS procedure has been applied NASA's Kepler mission observations of ~200,000 stars (Caceres, Dissertation Talk, this meeting) and will be applied in the future to other datasets.

Discussion as media and tool in PBL project-groups

DEFF Research Database (Denmark)

Spliid, Claus Monrad

2013-01-01

on the discussions which groups undertake in their pursuit of problem-solutions fulfilling assessed real-world needs as well as meeting the requirements of the educational program, it is concluded that discussions serve as a media for achieving learning and as a tool for developing skills essential for professional......The Aalborg PBL Model encourages project-management as a way for students to achieve efficiency and effectiveness in their study-projects. This paper looks into how the development of conversation skills relates to project-management as well as other factors. Through analysis of interviews focusing...

Stigmatizing materialism: on stereotypes and impressions of materialistic and experiential pursuits.

Science.gov (United States)

Van Boven, Leaf; Campbell, Margaret C; Gilovich, Thomas

2010-04-01

Five studies examined the stigmatization of materialism. Participants expressed negative stereotypes of materialistic people, considering them to be more selfish and self-centered than experiential people (Study 1). Participants also viewed materialistic pursuits as more extrinsically motivated than experiential pursuits (Study 2). These stereotypes led respondents from varied demographic backgrounds to form less favorable impressions of individuals who were associated with prototypically materialistic versus experiential purchases, a result that was statistically mediated by impressions that materialistic purchases were more extrinsically motivated (Study 3). These differential impressions are primarily attributable to the denigration of materialistic people rather than the admiration of experiential people (Study 4). The stigmatization of materialism led participants to like less and enjoy interacting less with their conversation partners when discussing materialistic rather than experiential purchases (Study 5). The authors discuss these findings' implications for self-perception, accurate social perception, and well-being.

Repeated Results Analysis for Middleware Regression Benchmarking

Czech Academy of Sciences Publication Activity Database

Bulej, Lubomír; Kalibera, T.; Tůma, P.

2005-01-01

Roč. 60, - (2005), s. 345-358 ISSN 0166-5316 R&D Projects: GA ČR GA102/03/0672 Institutional research plan: CEZ:AV0Z10300504 Keywords : middleware benchmarking * regression benchmarking * regression testing Subject RIV: JD - Computer Applications, Robotics Impact factor: 0.756, year: 2005

A Model of the Effects of Acceleration on a Pursuit Tracking Task

National Research Council Canada - National Science Library

McKinley, Richard A; Fullerton, Kathy L; Tripp, Jr., Lloyd D; Esken, Robert L; Goodyear, Chuck

2004-01-01

.... A mathematical model of this task could become useful when planning air combat missions. Eight subjects performed a 2-D manual pursuit tracking task during four different Gz conditions in a human centrifuge simulator...

Computing multiple-output regression quantile regions

Czech Academy of Sciences Publication Activity Database

Paindaveine, D.; Šiman, Miroslav

2012-01-01

Roč. 56, č. 4 (2012), s. 840-853 ISSN 0167-9473 R&D Projects: GA MŠk(CZ) 1M06047 Institutional research plan: CEZ:AV0Z10750506 Keywords : halfspace depth * multiple-output regression * parametric linear programming * quantile regression Subject RIV: BA - General Mathematics Impact factor: 1.304, year: 2012 http://library.utia.cas.cz/separaty/2012/SI/siman-0376413.pdf

Pursuit of Excellence in a Networked Society. : Theoretical and Practical Approaches.

NARCIS (Netherlands)

J. J.J.M. Volker; Dr. Marca Wolfensberger; Drs. L. Drayer

2014-01-01

Pursuit of Excellence in a Networked Society gives an overview of research and practice, describing and exploring efforts toward continuous improvement in programming to promote excellence. The talent development of students and teachers is a hot topic in today’s knowledge-based society which

The pursuit of perfect packing

CERN Document Server

Weaire, Denis

2000-01-01

In 1998 Thomas Hales dramatically announced the solution of a problem that has long teased eminent mathematicians: what is the densest possible arrangement of identical spheres? The Pursuit of Perfect Packing recounts the story of this problem and many others that have to do with packing things together. The examples are taken from mathematics, physics, biology, and engineering, including the arrangement of soap bubbles in foam, atoms in a crystal, the architecture of the bee''s honeycomb, and the structure of the Giant''s Causeway. Using an informal style and with key references, the book also includes brief accounts of the lives of many of the scientists who devoted themselves to problems of packing over many centuries, together with wry comments on their efforts. It is an entertaining introduction to the field for both specialists and the more general public.

Memory and decision-making in the frontal cortex during visual motion-processing for smooth pursuit eye movements

OpenAIRE

Shichinohe, N; Akao, T; Kurkin, S; Fukushima, J; Kaneko, CRS; Fukushima, K

2009-01-01

Cortical motor areas are thought to contribute "higher-order processing" but what that processing might include is unknown. Previous studies of the smooth pursuit-related discharge of supplementary eye field (SEF) neurons did not distinguish activity associated with the preparation for pursuit from discharge related to processing or memory of the target motion signals. Using a new, memory-based task, which was designed to separate these components, we show that the SEF contains signals coding...

Quantile Regression With Measurement Error

KAUST Repository

Wei, Ying; Carroll, Raymond J.

2009-01-01

. The finite sample performance of the proposed method is investigated in a simulation study, and compared to the standard regression calibration approach. Finally, we apply our methodology to part of the National Collaborative Perinatal Project growth data, a

Cerenkov luminescence tomography based on preconditioning orthogonal matching pursuit

Science.gov (United States)

Liu, Haixiao; Hu, Zhenhua; Wang, Kun; Tian, Jie; Yang, Xin

2015-03-01

Cerenkov luminescence imaging (CLI) is a novel optical imaging method and has been proved to be a potential substitute of the traditional radionuclide imaging such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). This imaging method inherits the high sensitivity of nuclear medicine and low cost of optical molecular imaging. To obtain the depth information of the radioactive isotope, Cerenkov luminescence tomography (CLT) is established and the 3D distribution of the isotope is reconstructed. However, because of the strong absorption and scatter, the reconstruction of the CLT sources is always converted to an ill-posed linear system which is hard to be solved. In this work, the sparse nature of the light source was taken into account and the preconditioning orthogonal matching pursuit (POMP) method was established to effectively reduce the ill-posedness and obtain better reconstruction accuracy. To prove the accuracy and speed of this algorithm, a heterogeneous numerical phantom experiment and an in vivo mouse experiment were conducted. Both the simulation result and the mouse experiment showed that our reconstruction method can provide more accurate reconstruction result compared with the traditional Tikhonov regularization method and the ordinary orthogonal matching pursuit (OMP) method. Our reconstruction method will provide technical support for the biological application for Cerenkov luminescence.

The pursuit of perfect packing

CERN Document Server

Weaire, Denis

2008-01-01

Coauthored by one of the creators of the most efficient space packing solution, the Weaire-Phelan structure, The Pursuit of Perfect Packing, Second Edition explores a problem of importance in physics, mathematics, chemistry, biology, and engineering: the packing of structures. Maintaining its mathematical core, this edition continues and revises some of the stories from its predecessor while adding several new examples and applications. The book focuses on both scientific and everyday problems ranging from atoms to honeycombs. It describes packing models, such as the Kepler conjecture, Voronoï decomposition, and Delaunay decomposition, as well as actual structure models, such as the Kelvin cell and the Weaire-Phelan structure. The authors discuss numerous historical aspects and provide biographical details on influential contributors to the field, including emails from Thomas Hales and Ken Brakke. With examples from physics, crystallography, engineering, and biology, this accessible and whimsical bo...

An integrated model of water resources optimization allocation based on projection pursuit model - Grey wolf optimization method in a transboundary river basin

Science.gov (United States)

Yu, Sen; Lu, Hongwei

2018-04-01

Under the effects of global change, water crisis ranks as the top global risk in the future decade, and water conflict in transboundary river basins as well as the geostrategic competition led by it is most concerned. This study presents an innovative integrated PPMGWO model of water resources optimization allocation in a transboundary river basin, which is integrated through the projection pursuit model (PPM) and Grey wolf optimization (GWO) method. This study uses the Songhua River basin and 25 control units as examples, adopting the PPMGWO model proposed in this study to allocate the water quantity. Using water consumption in all control units in the Songhua River basin in 2015 as reference to compare with optimization allocation results of firefly algorithm (FA) and Particle Swarm Optimization (PSO) algorithms as well as the PPMGWO model, results indicate that the average difference between corresponding allocation results and reference values are 0.195 bil m3, 0.151 bil m3, and 0.085 bil m3, respectively. Obviously, the average difference of the PPMGWO model is the lowest and its optimization allocation result is closer to reality, which further confirms the reasonability, feasibility, and accuracy of the PPMGWO model. And then the PPMGWO model is adopted to simulate allocation of available water quantity in Songhua River basin in 2018, 2020, and 2030. The simulation results show water quantity which could be allocated in all controls demonstrates an overall increasing trend with reasonable and equal exploitation and utilization of water resources in the Songhua River basin in future. In addition, this study has a certain reference value and application meaning to comprehensive management and water resources allocation in other transboundary river basins.

On Some Pursuit and Evasion Differential Game Problems for an Infinite Number of First-Order Differential Equations

Directory of Open Access Journals (Sweden)

Abbas Badakaya Ja'afaru

2012-01-01

Full Text Available We study pursuit and evasion differential game problems described by infinite number of first-order differential equations with function coefficients in Hilbert space l2. Problems involving integral, geometric, and mix constraints to the control functions of the players are considered. In each case, we give sufficient conditions for completion of pursuit and for which evasion is possible. Consequently, strategy of the pursuer and control function of the evader are constructed in an explicit form for every problem considered.

RHIC and the pursuit of the quark-gluon plasma

International Nuclear Information System (INIS)

Mitchell, J.T.

2001-01-01

There is a fugitive on the loose. Its name is Quark-Gluon Plasma, alias the QGP. The QGP is a known informant with knowledge about the fundamental building blocks of nature that we wish to extract. This briefing will outline the status of the pursuit of the elusive QGP. We will cover what makes the QGP tick, its modus operandi, details on how we plan to hunt the fugitive down, and our level of success thus far

Mass enhances speed but diminishes turn capacity in terrestrial pursuit predators

Science.gov (United States)

Wilson, Rory P; Griffiths, Iwan W; Mills, Michael GL; Carbone, Chris; Wilson, John W; Scantlebury, David M

2015-01-01

The dynamics of predator-prey pursuit appears complex, making the development of a framework explaining predator and prey strategies problematic. We develop a model for terrestrial, cursorial predators to examine how animal mass modulates predator and prey trajectories and affects best strategies for both parties. We incorporated the maximum speed-mass relationship with an explanation of why larger animals should have greater turn radii; the forces needed to turn scale linearly with mass whereas the maximum forces an animal can exert scale to a 2/3 power law. This clarifies why in a meta-analysis, we found a preponderance of predator/prey mass ratios that minimized the turn radii of predators compared to their prey. It also explained why acceleration data from wild cheetahs pursuing different prey showed different cornering behaviour with prey type. The outcome of predator prey pursuits thus depends critically on mass effects and the ability of animals to time turns precisely. DOI: http://dx.doi.org/10.7554/eLife.06487.001 PMID:26252515

Visual and non-visual motion information processing during pursuit eye tracking in schizophrenia and bipolar disorder.

Science.gov (United States)

Trillenberg, Peter; Sprenger, Andreas; Talamo, Silke; Herold, Kirsten; Helmchen, Christoph; Verleger, Rolf; Lencer, Rebekka

2017-04-01

Despite many reports on visual processing deficits in psychotic disorders, studies are needed on the integration of visual and non-visual components of eye movement control to improve the understanding of sensorimotor information processing in these disorders. Non-visual inputs to eye movement control include prediction of future target velocity from extrapolation of past visual target movement and anticipation of future target movements. It is unclear whether non-visual input is impaired in patients with schizophrenia. We recorded smooth pursuit eye movements in 21 patients with schizophrenia spectrum disorder, 22 patients with bipolar disorder, and 24 controls. In a foveo-fugal ramp task, the target was either continuously visible or was blanked during movement. We determined peak gain (measuring overall performance), initial eye acceleration (measuring visually driven pursuit), deceleration after target extinction (measuring prediction), eye velocity drifts before onset of target visibility (measuring anticipation), and residual gain during blanking intervals (measuring anticipation and prediction). In both patient groups, initial eye acceleration was decreased and the ability to adjust eye acceleration to increasing target acceleration was impaired. In contrast, neither deceleration nor eye drift velocity was reduced in patients, implying unimpaired non-visual contributions to pursuit drive. Disturbances of eye movement control in psychotic disorders appear to be a consequence of deficits in sensorimotor transformation rather than a pure failure in adding cognitive contributions to pursuit drive in higher-order cortical circuits. More generally, this deficit might reflect a fundamental imbalance between processing external input and acting according to internal preferences.

On weighted and locally polynomial directional quantile regression

Czech Academy of Sciences Publication Activity Database

Boček, Pavel; Šiman, Miroslav

2017-01-01

Roč. 32, č. 3 (2017), s. 929-946 ISSN 0943-4062 R&D Projects: GA ČR GA14-07234S Institutional support: RVO:67985556 Keywords : Quantile regression * Nonparametric regression * Nonparametric regression Subject RIV: IN - Informatics, Computer Science OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 0.434, year: 2016 http://library.utia.cas.cz/separaty/2017/SI/bocek-0458380.pdf

On directional multiple-output quantile regression

Czech Academy of Sciences Publication Activity Database

Paindaveine, D.; Šiman, Miroslav

2011-01-01

Roč. 102, č. 2 (2011), s. 193-212 ISSN 0047-259X R&D Projects: GA MŠk(CZ) 1M06047 Grant - others:Commision EC(BE) Fonds National de la Recherche Scientifique Institutional research plan: CEZ:AV0Z10750506 Keywords : multivariate quantile * quantile regression * multiple-output regression * halfspace depth * portfolio optimization * value-at risk Subject RIV: BA - General Mathematics Impact factor: 0.879, year: 2011 http://library.utia.cas.cz/separaty/2011/SI/siman-0364128.pdf

Differential games a mathematical theory with applications to warfare and pursuit, control and optimization

CERN Document Server

Isaacs, Rufus

1999-01-01

Definitive work draws on game theory, calculus of variations, and control theory to solve an array of problems: military, pursuit and evasion, athletic contests, many more. Detailed examples, formal calculations. 1965 edition.

The pursuit of happiness: time, money, and social connection.

Science.gov (United States)

Mogilner, Cassie

2010-09-01

Does thinking about time, rather than money, influence how effectively individuals pursue personal happiness? Laboratory and field experiments revealed that implicitly activating the construct of time motivates individuals to spend more time with friends and family and less time working-behaviors that are associated with greater happiness. In contrast, implicitly activating money motivates individuals to work more and socialize less, which (although productive) does not increase happiness. Implications for the relative roles of time versus money in the pursuit of happiness are discussed.

Culture, cognition and behavior in the pursuit of self-esteem

DEFF Research Database (Denmark)

Strandell, Jacob

2016-01-01

to reconcile constructionist views of identity with a cognitive self is therefore suggested and discussed. By drawing on models of neuro-cognition, it is possible to think of a cognitive self as performed, context-dependent and emergent rather than fixed, internal and expressed. Finally, the paper discusses...... the social contingencies and consequences of self-esteem pursuits in relation to research issues such as aggression, stratification, crime, masculinity, and political attitudes....

Learning a Nonnegative Sparse Graph for Linear Regression.

Science.gov (United States)

Fang, Xiaozhao; Xu, Yong; Li, Xuelong; Lai, Zhihui; Wong, Wai Keung

2015-09-01

Previous graph-based semisupervised learning (G-SSL) methods have the following drawbacks: 1) they usually predefine the graph structure and then use it to perform label prediction, which cannot guarantee an overall optimum and 2) they only focus on the label prediction or the graph structure construction but are not competent in handling new samples. To this end, a novel nonnegative sparse graph (NNSG) learning method was first proposed. Then, both the label prediction and projection learning were integrated into linear regression. Finally, the linear regression and graph structure learning were unified within the same framework to overcome these two drawbacks. Therefore, a novel method, named learning a NNSG for linear regression was presented, in which the linear regression and graph learning were simultaneously performed to guarantee an overall optimum. In the learning process, the label information can be accurately propagated via the graph structure so that the linear regression can learn a discriminative projection to better fit sample labels and accurately classify new samples. An effective algorithm was designed to solve the corresponding optimization problem with fast convergence. Furthermore, NNSG provides a unified perceptiveness for a number of graph-based learning methods and linear regression methods. The experimental results showed that NNSG can obtain very high classification accuracy and greatly outperforms conventional G-SSL methods, especially some conventional graph construction methods.

Elliptical multiple-output quantile regression and convex optimization

Czech Academy of Sciences Publication Activity Database

Hallin, M.; Šiman, Miroslav

2016-01-01

Roč. 109, č. 1 (2016), s. 232-237 ISSN 0167-7152 R&D Projects: GA ČR GA14-07234S Institutional support: RVO:67985556 Keywords : quantile regression * elliptical quantile * multivariate quantile * multiple-output regression Subject RIV: BA - General Mathematics Impact factor: 0.540, year: 2016 http://library.utia.cas.cz/separaty/2016/SI/siman-0458243.pdf

Rotorcraft pursuit-evasion in nap-of-the-earth flight

Science.gov (United States)

Menon, P. K. A.; Cheng, V. H. L.; Kim, E.

1990-01-01

Two approaches for studying the pursuit-evasion problem between rotorcraft executing nap-of-the-earth flight are presented. The first of these employs a constant speed kinematic helicopter model, while the second approach uses a three degree of freedom point-mass model. The candidate solutions to the first differential game are generated by integrating the state-costate equations backward in time. The second problem employs feedback linearization to obtain guidance laws in nonlinear feedback form. Both approaches explicitly use the terrain profile data. Sample extremals are presented.

In Pursuit of Happiness, Bhutan Opens to Globalization and Business

OpenAIRE

Kimberly A. Freeman, Ph.D.; Katherine C. Jackson

2013-01-01

The Kingdom of Bhutan, a small country situated on the border between China and India, has in recent years become a constitutional democratic monarchy. As part of its 2008 constitution, Bhutan committed to promote conditions that would enable the pursuit of Gross National Happiness. The countrythus initiated an effort to improve the quality of life and happiness for its citizens and has embraced globalization far more than previouslythrough attracting business, tourism, and communications. Th...

Reciprocal feedback between self-concept and goal pursuit in daily life.

Science.gov (United States)

Wong, Alexander E; Vallacher, Robin R

2018-06-01

We hypothesized that self-knowledge and goal perseverance are mutually reinforcing because of the roles of self-knowledge in directing goal pursuit, and of goal pursuit in structuring the self-concept. To test this hypothesis, we used a daily diary design with 97 college-aged participants for 40 days to assess whether daily self-concept clarity and grit predict one another's next-day levels. Data were analyzed using multilevel cross-lagged panel modeling. Results indicated that daily self-concept clarity and grit had positive and symmetric associations with each other across time, while controlling for their respective previous values. Similar crossed results were also found when testing the model using individual daily self-concept clarity and grit items. The results are the first to indicate the existence of reinforcing feedback loops between self-concept clarity and grit, such that fluctuations in the clarity of self-knowledge are associated with fluctuations in goal resolve, and vice versa. Discussion centers on the implications of these results for the functional link between mind and action and on the study's heuristic value for subsequent research. © 2017 Wiley Periodicals, Inc.

Getting started in radio astronomy beginner projects for the amateur

CERN Document Server

Arnold, Steven

2013-01-01

Radio astronomy is a mystery to the majority of amateur astronomers, yet it is the best subject to turn to when desirous of an expanded knowledge of the sky. This guide intends to instruct complete newcomers to radio astronomy, and provides help for the first steps on the road towards the study of this fascinating subject. In addition to a history of the science behind the pursuit, directions are included for four easy-to-build projects, based around long-term NASA and Stanford Solar Center projects. The first three projects constitute self-contained units available as kits, so there is no nee

In the Pursuit of Sons: Additional Births or Sex-Selective Abortion in Pakistan?

Science.gov (United States)

Zaidi, Batool; Morgan, S Philip

2016-12-01

Even though Pakistan is a highly patriarchal society, it has not featured prominently in studies focusing on sex-selective abortion and sex ratios at birth. But with fertility declining and existing strong son preference-Pakistan has one of the highest desired sex ratios in the world-how will Pakistani families respond? In the pursuit of sons, will they have additional children or resort to sex-selective abortions? Or is there evidence that the pursuit of sons is weakening? Using data from three rounds of the demographic and health survey, we show clear evidence of son preference in fertility intentions, patterns of contraceptive use and parity progression ratios. More specifically, we find pervasive evidence that Pakistanis continue childbearing to have a son, to have more than one son and to have at least one daughter. We do not find consistent and convincing evidence that sex ratios at birth (which indicate sex-selective abortion) are increasing.

Culture shapes whether the pursuit of happiness predicts higher or lower well-being

Science.gov (United States)

Ford, Brett Q.; Dmitrieva, Julia O.; Heller, Daniel; Chentsova-Dutton, Yulia; Grossmann, Igor; Tamir, Maya; Uchida, Yukiko; Koopmann-Holm, Birgit; Floerke, Victoria A.; Uhrig, Meike; Bokhan, Tatiana; Mauss, Iris B.

2015-01-01

Pursuing happiness can paradoxically impair well-being. Here, we propose the potential downsides to pursuing happiness may be specific to individualistic cultures. In collectivistic (vs. individualistic) cultures, pursuing happiness may be more successful because happiness is viewed – and thus pursued – in relatively socially-engaged ways. In four geographical regions that vary in level of collectivism (U.S., Germany, Russia, East Asia), we assessed participants’ well-being, motivation to pursue happiness, and to what extent they pursued happiness in socially-engaged ways. Motivation to pursue happiness predicted lower well-being in the U.S., did not predict well-being in Germany, and predicted higher well-being in Russia and in East Asia. These cultural differences in the link between motivation to pursue happiness and well-being were explained by cultural differences in the socially-engaged pursuit of happiness. These findings suggest that culture shapes whether the pursuit of happiness is linked with better or worse well-being, perhaps via how people pursue happiness. PMID:26347945

Comparing fMRI activation during smooth pursuit eye movements among contact sport athletes, non-contact sport athletes, and non-athletes

Directory of Open Access Journals (Sweden)

Derek Kellar

Full Text Available Objectives: Though sub-concussive impacts are common during contact sports, there is little consensus whether repeat blows affect brain function. Using a “lifetime exposure” rather than acute exposure approach, we examined oculomotor performance and brain activation among collegiate football players and two control groups. Our analysis examined whether there are group differences in eye movement behavioral performance and in brain activation during smooth pursuit. Methods: Data from 21 off-season Division I football “starters” were compared with a 19 collegiate cross-country runners, and b 11 non-athlete college students who were SES matched to the football player group (total N = 51. Visual smooth pursuit was performed while undergoing fMRI imaging via a 3 Tesla scanner. Smooth pursuit eye movements to three stimulus difficulty levels were measured with regard to RMS error, gain, and lag. Results: No meaningful differences were found for any of the standard analyses used to assess smooth pursuit eye movements. For fMRI, greater activation was seen in the oculomotor region of the cerebellar vermis and areas of the FEF for football players as compared to either control group, who did not differ on any measure. Conclusion: Greater cerebellar activity among football players while performing an oculomotor task could indicate that they are working harder to compensate for some subtle, long-term subconcussive deficits. Alternatively, top athletes in a sport requiring high visual motor skill could have more of their cerebellum and FEF devoted to oculomotor task performance regardless of subconcussive history. Overall, these results provide little firm support for an effect of accumulated subconcussion exposure on brain function. Keywords: Smooth pursuit, fMRI, Collegiate athletics

Pursuit of Muscularity in Adolescent Boys: Relations among Biopsychosocial Variables and Clinical Outcomes

Science.gov (United States)

Cafri, Guy; van den Berg, Patricia; Thompson, J. Kevin

2006-01-01

Adolescent boys (n = 269) were assessed for levels of several risky behaviors related to the pursuit of muscularity, including substance use (anabolic steroids, prohormones, and ephedrine) dieting to gain weight, and symptoms of muscle dysmorphia (MD). The association between these behaviors and a variety of putative biological, psychological, and…

Origins of the Human Genome Project

Science.gov (United States)

Cook-Deegan, Robert (Affiliation: Institute of Medicine, National Academy of Sciences)

1993-07-01

The human genome project was borne of technology, grew into a science bureaucracy in the United States and throughout the world, and is now being transformed into a hybrid academic and commercial enterprise. The next phase of the project promises to veer more sharply toward commercial application, harnessing both the technical prowess of molecular biology and the rapidly growing body of knowledge about DNA structure to the pursuit of practical benefits. Faith that the systematic analysis of DNA structure will prove to be a powerful research tool underlies the rationale behind the genome project. The notion that most genetic information is embedded in the sequence of CNA base pairs comprising chromosomes is a central tenet. A rough analogy is to liken an organism's genetic code to computer code. The coal of the genome project, in this parlance, is to identify and catalog 75,000 or more files (genes) in the software that directs construction of a self-modifying and self-replicating system -- a living organism.

Origins of the Human Genome Project

Energy Technology Data Exchange (ETDEWEB)

Cook-Deegan, Robert

1993-07-01

The human genome project was borne of technology, grew into a science bureaucracy in the US and throughout the world, and is now being transformed into a hybrid academic and commercial enterprise. The next phase of the project promises to veer more sharply toward commercial application, harnessing both the technical prowess of molecular biology and the rapidly growing body of knowledge about DNA structure to the pursuit of practical benefits. Faith that the systematic analysis of DNA structure will prove to be a powerful research tool underlies the rationale behind the genome project. The notion that most genetic information is embedded in the sequence of CNA base pairs comprising chromosomes is a central tenet. A rough analogy is to liken an organism's genetic code to computer code. The coal of the genome project, in this parlance, is to identify and catalog 75,000 or more files (genes) in the software that directs construction of a self-modifying and self-replicating system -- a living organism.

Vectors, a tool in statistical regression theory

NARCIS (Netherlands)

Corsten, L.C.A.

1958-01-01

Using linear algebra this thesis developed linear regression analysis including analysis of variance, covariance analysis, special experimental designs, linear and fertility adjustments, analysis of experiments at different places and times. The determination of the orthogonal projection, yielding

Biomechanical justification of the choice of optimum mode for passing the individual pursuit race

Directory of Open Access Journals (Sweden)

A.N. Kolumbet

2018-04-01

Full Text Available Purpose : biomechanical justification of the choice of optimum mode of passing competitive distance of 4 km individual pursuit on track. Material : The qualified cyclists (n=14 participated in researches. The modified stationary cycle Monark was used. Cyclists performed work in two modes - A and B. Results : The mode B is physiologically more favorable. The mode B should be considered as a model of passing a distance in preliminary races of individual pursuit. Work in the mode A demands terminal mobilization of organism functions. Work in the mode A is more effective in the achievement of sports result. It can be used only once in the final race of competitions. Conclusions : The received data should be considered as a demonstration of specific features of passing a distance in the competitive modes. The tactical variant of competitive program creation is defined by the individual functional state.

Similar effects of feature-based attention on motion perception and pursuit eye movements at different levels of awareness.

Science.gov (United States)

Spering, Miriam; Carrasco, Marisa

2012-05-30

Feature-based attention enhances visual processing and improves perception, even for visual features that we are not aware of. Does feature-based attention also modulate motor behavior in response to visual information that does or does not reach awareness? Here we compare the effect of feature-based attention on motion perception and smooth-pursuit eye movements in response to moving dichoptic plaids--stimuli composed of two orthogonally drifting gratings, presented separately to each eye--in human observers. Monocular adaptation to one grating before the presentation of both gratings renders the adapted grating perceptually weaker than the unadapted grating and decreases the level of awareness. Feature-based attention was directed to either the adapted or the unadapted grating's motion direction or to both (neutral condition). We show that observers were better at detecting a speed change in the attended than the unattended motion direction, indicating that they had successfully attended to one grating. Speed change detection was also better when the change occurred in the unadapted than the adapted grating, indicating that the adapted grating was perceptually weaker. In neutral conditions, perception and pursuit in response to plaid motion were dissociated: While perception followed one grating's motion direction almost exclusively (component motion), the eyes tracked the average of both gratings (pattern motion). In attention conditions, perception and pursuit were shifted toward the attended component. These results suggest that attention affects perception and pursuit similarly even though only the former reflects awareness. The eyes can track an attended feature even if observers do not perceive it.

Competence over Communion: Implicit Evaluations of Personality Traits During Goal Pursuit

Directory of Open Access Journals (Sweden)

Roczniewska Marta

2014-12-01

Full Text Available Research shows that goal-relevant objects are rated positively, which results from their functionality towards the aim. In previous studies these objects were always external to the agent. However, relevant knowledge of self is also potentially accessible during goal pursuit, as self-esteem is an indicator of aim’s feasibility. In two experimental studies we tested whether goal activation affects temporal changes in automatic evaluations of personality traits related to the dimensions of agency and communion. We administered affect misattribution procedure where participants rated neutral Chinese hexagrams proceeded by words describing traits (75 ms masked presentation. The list of words comprised agentic (e.g. agile and communal (e.g. trustworthy traits. The rating took place twice - before and after introducing a manual task. In the first study, goal activation led to slightly more positive implicit evaluations of agentic and more negative evaluation of communal traits, which is consistent with empirical data on self-perception depending on agentic knowledge rather than communal one. In the second study we showed that goal activation led to changes only for promotion-, but not prevention-oriented individuals, which is explained by motivation strength. The results indicate that valuation of traits changes temporarily along with goal pursuit.

Directional quantile regression in R

Czech Academy of Sciences Publication Activity Database

Boček, Pavel; Šiman, Miroslav

2017-01-01

Roč. 53, č. 3 (2017), s. 480-492 ISSN 0023-5954 R&D Projects: GA ČR GA14-07234S Institutional support: RVO:67985556 Keywords : multivariate quantile * regression quantile * halfspace depth * depth contour Subject RIV: BD - Theory of Information OBOR OECD: Applied mathematics Impact factor: 0.379, year: 2016 http://library.utia.cas.cz/separaty/2017/SI/bocek-0476587.pdf

Robust median estimator in logisitc regression

Czech Academy of Sciences Publication Activity Database

Hobza, T.; Pardo, L.; Vajda, Igor

2008-01-01

Roč. 138, č. 12 (2008), s. 3822-3840 ISSN 0378-3758 R&D Projects: GA MŠk 1M0572 Grant - others:Instituto Nacional de Estadistica (ES) MPO FI - IM3/136; GA MŠk(CZ) MTM 2006-06872 Institutional research plan: CEZ:AV0Z10750506 Keywords : Logistic regression * Median * Robustness * Consistency and asymptotic normality * Morgenthaler * Bianco and Yohai * Croux and Hasellbroeck Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.679, year: 2008 http://library.utia.cas.cz/separaty/2008/SI/vajda-robust%20median%20estimator%20in%20logistic%20regression.pdf

Fixed Duration Pursuit-Evasion Differential Game with Integral Constraints

International Nuclear Information System (INIS)

Ibragimov G I; Kuchkarov A Sh

2013-01-01

We investigate a pursuit-evasion differential game of countably many pursuers and one evader. Integral constraints are imposed on control functions of the players. Duration of the game is fixed and the payoff of the game is infimum of the distances between the evader and pursuers when the game is completed. Purpose of the pursuers is to minimize the payoff and that of the evader is to maximize it. Optimal strategies of the players are constructed, and the value of the game is found. It should be noted that energy resource of any pursuer may be less than that of the evader.

Sparse reconstruction using distribution agnostic bayesian matching pursuit

KAUST Repository

Masood, Mudassir

2013-11-01

A fast matching pursuit method using a Bayesian approach is introduced for sparse signal recovery. This method performs Bayesian estimates of sparse signals even when the signal prior is non-Gaussian or unknown. It is agnostic on signal statistics and utilizes a priori statistics of additive noise and the sparsity rate of the signal, which are shown to be easily estimated from data if not available. The method utilizes a greedy approach and order-recursive updates of its metrics to find the most dominant sparse supports to determine the approximate minimum mean-square error (MMSE) estimate of the sparse signal. Simulation results demonstrate the power and robustness of our proposed estimator. © 2013 IEEE.

Zero-Shot Learning via Attribute Regression and Class Prototype Rectification.

Science.gov (United States)

Luo, Changzhi; Li, Zhetao; Huang, Kaizhu; Feng, Jiashi; Wang, Meng

2018-02-01

Zero-shot learning (ZSL) aims at classifying examples for unseen classes (with no training examples) given some other seen classes (with training examples). Most existing approaches exploit intermedia-level information (e.g., attributes) to transfer knowledge from seen classes to unseen classes. A common practice is to first learn projections from samples to attributes on seen classes via a regression method, and then apply such projections to unseen classes directly. However, it turns out that such a manner of learning strategy easily causes projection domain shift problem and hubness problem, which hinder the performance of ZSL task. In this paper, we also formulate ZSL as an attribute regression problem. However, different from general regression-based solutions, the proposed approach is novel in three aspects. First, a class prototype rectification method is proposed to connect the unseen classes to the seen classes. Here, a class prototype refers to a vector representation of a class, and it is also known as a class center, class signature, or class exemplar. Second, an alternating learning scheme is proposed for jointly performing attribute regression and rectifying the class prototypes. Finally, a new objective function which takes into consideration both the attribute regression accuracy and the class prototype discrimination is proposed. By introducing such a solution, domain shift problem and hubness problem can be mitigated. Experimental results on three public datasets (i.e., CUB200-2011, SUN Attribute, and aPaY) well demonstrate the effectiveness of our approach.

Intellectual Pursuits of Young Children through Picture Book Literacy, Focusing on Italian Preschools

Science.gov (United States)

Beltchenko, Laura

2016-01-01

In this article, I will examine the use of picture books as a means of supporting the intellectual pursuits of young children. Theoretical frameworks will be discussed as they pertain to the integration of these books in the Municipal Infant Toddler Centers and Preschools of Reggio Emilia and Pistoia, Italy. The pedagogical framework of these…

Culture shapes whether the pursuit of happiness predicts higher or lower well-being.

Science.gov (United States)

Ford, Brett Q; Dmitrieva, Julia O; Heller, Daniel; Chentsova-Dutton, Yulia; Grossmann, Igor; Tamir, Maya; Uchida, Yukiko; Koopmann-Holm, Birgit; Floerke, Victoria A; Uhrig, Meike; Bokhan, Tatiana; Mauss, Iris B

2015-12-01

Pursuing happiness can paradoxically impair well-being. Here, the authors propose the potential downsides to pursuing happiness may be specific to individualistic cultures. In collectivistic (vs. individualistic) cultures, pursuing happiness may be more successful because happiness is viewed--and thus pursued--in relatively socially engaged ways. In 4 geographical regions that vary in level of collectivism (United States, Germany, Russia, East Asia), we assessed participants' well-being, motivation to pursue happiness, and to what extent they pursued happiness in socially engaged ways. Motivation to pursue happiness predicted lower well-being in the United States, did not predict well-being in Germany, and predicted higher well-being in Russia and in East Asia. These cultural differences in the link between motivation to pursue happiness and well-being were explained by cultural differences in the socially engaged pursuit of happiness. These findings suggest that culture shapes whether the pursuit of happiness is linked with better or worse well-being, perhaps via how people pursue happiness. (c) 2015 APA, all rights reserved).

Effects of reward on the accuracy and dynamics of smooth pursuit eye movements.

Science.gov (United States)

Brielmann, Aenne A; Spering, Miriam

2015-08-01

Reward modulates behavioral choices and biases goal-oriented behavior, such as eye or hand movements, toward locations or stimuli associated with higher rewards. We investigated reward effects on the accuracy and timing of smooth pursuit eye movements in 4 experiments. Eye movements were recorded in participants tracking a moving visual target on a computer monitor. Before target motion onset, a monetary reward cue indicated whether participants could earn money by tracking accurately, or whether the trial was unrewarded (Experiments 1 and 2, n = 11 each). Reward significantly improved eye-movement accuracy across different levels of task difficulty. Improvements were seen even in the earliest phase of the eye movement, within 70 ms of tracking onset, indicating that reward impacts visual-motor processing at an early level. We obtained similar findings when reward was not precued but explicitly associated with the pursuit target (Experiment 3, n = 16); critically, these results were not driven by stimulus prevalence or other factors such as preparation or motivation. Numerical cues (Experiment 4, n = 9) were not effective. (c) 2015 APA, all rights reserved).

Differentiating regressed melanoma from regressed lichenoid keratosis.

Science.gov (United States)

Chan, Aegean H; Shulman, Kenneth J; Lee, Bonnie A

2017-04-01

Distinguishing regressed lichen planus-like keratosis (LPLK) from regressed melanoma can be difficult on histopathologic examination, potentially resulting in mismanagement of patients. We aimed to identify histopathologic features by which regressed melanoma can be differentiated from regressed LPLK. Twenty actively inflamed LPLK, 12 LPLK with regression and 15 melanomas with regression were compared and evaluated by hematoxylin and eosin staining as well as Melan-A, microphthalmia transcription factor (MiTF) and cytokeratin (AE1/AE3) immunostaining. (1) A total of 40% of regressed melanomas showed complete or near complete loss of melanocytes within the epidermis with Melan-A and MiTF immunostaining, while 8% of regressed LPLK exhibited this finding. (2) Necrotic keratinocytes were seen in the epidermis in 33% regressed melanomas as opposed to all of the regressed LPLK. (3) A dense infiltrate of melanophages in the papillary dermis was seen in 40% of regressed melanomas, a feature not seen in regressed LPLK. In summary, our findings suggest that a complete or near complete loss of melanocytes within the epidermis strongly favors a regressed melanoma over a regressed LPLK. In addition, necrotic epidermal keratinocytes and the presence of a dense band-like distribution of dermal melanophages can be helpful in differentiating these lesions. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Home and Motivational Factors Related to Science-Career Pursuit: Gender differences and gender similarities

Science.gov (United States)

Shin, Jongho; Lee, Hyunjoo; McCarthy-Donovan, Alexander; Hwang, Hyeyoung; Yim, Sonyoung; Seo, EunJin

2015-06-01

The purpose of the study was to examine whether gender differences exist in the mean levels of and relations between adolescents' home environments (parents' view of science, socio-economic status (SES)), motivations (intrinsic and instrumental motivations, self-beliefs), and pursuit of science careers. For the purpose, the Programmed for International Student Assessment 2006 data of Korean 15-year-old students were analysed. The results of the study showed that girls had lower levels of science intrinsic and instrumental motivations, self-beliefs, and science-career pursuit (SCP) as well as their parents' values in science less than boys. Gender similarities, rather than gender differences, existed in patterns of causal relationship among home environments, motivations, and SCP. The results showed positive effects for parents' higher value in science and SES on motivations, SCP, and for intrinsic and instrumental motivations on SCP for girls and boys. These results provide implications for educational interventions to decrease gender differences in science motivations and SCP, and to decrease adolescents' gender stereotypes.

Nonevent stress contributes to mental health disparities based on sexual orientation: evidence from a personal projects analysis.

Science.gov (United States)

Frost, David M; LeBlanc, Allen J

2014-09-01

This study examined the role of nonevent stress--in the form of frustrated personal project pursuits in the arenas of relationships and work--as a contributing factor to mental health disparities between heterosexual and lesbian, gay, and bisexual (LGB) populations. A purposive sample of 431 LGB (55%) and heterosexually identified (45%) individuals living in the United States and Canada completed the Personal Project Inventory by describing and rating core personal projects they were pursuing. The intensity of perceived barriers to the achievement of relationship- and work-related personal projects served as indicators nonevent stress. Hierarchical linear regression models tested the hypothesis that nonevent stress contributes to the association between sexual orientation and two indicators of mental health: depressive symptoms and psychological well-being. LGB individuals had significantly more depressive symptoms and lower levels of psychological well-being than heterosexuals. Indicators of nonevent stress were significantly associated with mental health outcomes and their inclusion in models attenuated sexual orientation differences in mental health. The critical indirect pathway leading from sexual minority status to mental health occurred via barriers to relationship projects from interpersonal sources. This research suggests that nonevent stress because of structural and interpersonal stigma may contribute to mental health disparities between LGB and heterosexual individuals. The findings have important implications for policy reform around same-sex relationship recognition and workplace discrimination. Future research and clinical work will benefit by expanding existing foci on stress to include nonevent stressors to better understand and address mental health problems, particularly in LGB populations.

Quantile Regression With Measurement Error

KAUST Repository

Wei, Ying

2009-08-27

Regression quantiles can be substantially biased when the covariates are measured with error. In this paper we propose a new method that produces consistent linear quantile estimation in the presence of covariate measurement error. The method corrects the measurement error induced bias by constructing joint estimating equations that simultaneously hold for all the quantile levels. An iterative EM-type estimation algorithm to obtain the solutions to such joint estimation equations is provided. The finite sample performance of the proposed method is investigated in a simulation study, and compared to the standard regression calibration approach. Finally, we apply our methodology to part of the National Collaborative Perinatal Project growth data, a longitudinal study with an unusual measurement error structure. © 2009 American Statistical Association.

Career Pursuit Pathways among Emerging Adult Men and Women: Psychosocial Correlates and Precursors

Science.gov (United States)

Shulman, Shmuel; Barr, Tamuz; Livneh, Yaara; Nurmi, Jari-Erik; Vasalampi, Kati; Pratt, Michael

2015-01-01

The present study examined career pursuit pathways in 100 Israeli emerging adults (54 men) who were followed from age 22 to 29. Employing a semi-structured interview at the age of 29, participants were asked about current work and educational status, work and educational goals and status changes in recent years, and to reflect on the meaning of…

In Pursuit of Happiness, Bhutan Opens to Globalization and Business

Directory of Open Access Journals (Sweden)

Kimberly A. Freeman, Ph.D.

2013-07-01

Full Text Available The Kingdom of Bhutan, a small country situated on the border between China and India, has in recent years become a constitutional democratic monarchy. As part of its 2008 constitution, Bhutan committed to promote conditions that would enable the pursuit of Gross National Happiness. The countrythus initiated an effort to improve the quality of life and happiness for its citizens and has embraced globalization far more than previouslythrough attracting business, tourism, and communications. The author’s hereinaddress some of the initiatives provide the context within which these efforts have arisen.

Home and Motivational Factors Related to Science-Career Pursuit: Gender Differences and Gender Similarities

Science.gov (United States)

Shin, Jongho; Lee, Hyunjoo; McCarthy-Donovan, Alexander; Hwang, Hyeyoung; Yim, Sonyoung; Seo, EunJin

2015-01-01

The purpose of the study was to examine whether gender differences exist in the mean levels of and relations between adolescents' home environments (parents' view of science, socio-economic status (SES)), motivations (intrinsic and instrumental motivations, self-beliefs), and pursuit of science careers. For the purpose, the Programmed for…

The Collinearity Free and Bias Reduced Regression Estimation Project: The Theory of Normalization Ridge Regression. Report No. 2.

Science.gov (United States)

Bulcock, J. W.; And Others

Multicollinearity refers to the presence of highly intercorrelated independent variables in structural equation models, that is, models estimated by using techniques such as least squares regression and maximum likelihood. There is a problem of multicollinearity in both the natural and social sciences where theory formulation and estimation is in…

The Pursuit of Sustainable Competitive Advantage : A Profile of the Starbucks Corporation

OpenAIRE

White, Benjamin; Moraschinelli, Ettore

2009-01-01

Title: The Pursuit of Sustainable Competitive Advantage – A Profile of the Starbucks Corporation Authors: Benjamin Adam White & Ettore Moraschinelli Advisor: Jean-Charles Languilaire Date: 2009 May 29 Program: International Business and Entrepreneurship Purpose: To study sustainable competitive advantages using Starbucks as a case study. Methods: The qualitative method was utilized to collect the secondary data used in this type of thesis, being a case study. This approach applied to both...

Life goal attainment in the adaptation process after acquired brain injury: the influence of self-efficacy and of flexibility and tenacity in goal pursuit.

Science.gov (United States)

Brands, Ingrid; Stapert, Sven; Köhler, Sebastian; Wade, Derick; van Heugten, Caroline

2015-06-01

To investigate attainment of important life goals and to examine whether self-efficacy, tenacity in goal pursuit and flexibility in goal adjustment contribute to adaptation by affecting levels of emotional distress and quality of life in patients with newly acquired brain injury. Data were collected from a prospective clinical cohort study of 148 patients assessed after discharge home (mean time since injury = 15 weeks) and one year later. At follow-up, attainment of life goals (set at baseline) and satisfaction with attainment was scored (10-point scale) and patients were asked how they adjusted unattained goals. Emotional distress was measured with the Hospital Anxiety and Depression Scale (HADS), quality of life with the Life Satisfaction Questionnaire (LiSat-9), self-efficacy with the TBI Self-efficacy Questionnaire (SEsx) and tenacity and flexibility with the Assimilative/Accommodative Coping Questionnaire (AACQ). Random effects regression analyses and structural equation modelling were used. In total, only 13 % of initial life goals were achieved in one year. Patients who maintained efforts to reach their original goals had higher average levels of tenacity, but did not differ in level of self-efficacy compared with patients that disengaged. Patients with higher self-efficacy were more successful in attaining important life goals, which correlated with higher quality of life. Patients with higher self-efficacy, higher tenacity in goal pursuit, and higher flexibility in goal adjustment were less emotionally distressed, again correlating with higher quality of life. To optimise adaptation it seems appropriate to promote self-efficacy and both tenacity and flexibility during rehabilitation treatment. © The Author(s) 2014.

Superquantile Regression: Theory, Algorithms, and Applications

Science.gov (United States)

2014-12-01

Highway, Suite 1204, Arlington, Va 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188) Washington DC 20503. 1...Navy submariners, reliability engineering, uncertainty quantification, and financial risk management . Superquantile, superquantile regression...Royset Carlos F. Borges Associate Professor of Operations Research Dissertation Supervisor Professor of Applied Mathematics Lyn R. Whitaker Javier

Matrix-Inversion-Free Compressed Sensing With Variable Orthogonal Multi-Matching Pursuit Based on Prior Information for ECG Signals.

Science.gov (United States)

Cheng, Yih-Chun; Tsai, Pei-Yun; Huang, Ming-Hao

2016-05-19

Low-complexity compressed sensing (CS) techniques for monitoring electrocardiogram (ECG) signals in wireless body sensor network (WBSN) are presented. The prior probability of ECG sparsity in the wavelet domain is first exploited. Then, variable orthogonal multi-matching pursuit (vOMMP) algorithm that consists of two phases is proposed. In the first phase, orthogonal matching pursuit (OMP) algorithm is adopted to effectively augment the support set with reliable indices and in the second phase, the orthogonal multi-matching pursuit (OMMP) is employed to rescue the missing indices. The reconstruction performance is thus enhanced with the prior information and the vOMMP algorithm. Furthermore, the computation-intensive pseudo-inverse operation is simplified by the matrix-inversion-free (MIF) technique based on QR decomposition. The vOMMP-MIF CS decoder is then implemented in 90 nm CMOS technology. The QR decomposition is accomplished by two systolic arrays working in parallel. The implementation supports three settings for obtaining 40, 44, and 48 coefficients in the sparse vector. From the measurement result, the power consumption is 11.7 mW at 0.9 V and 12 MHz. Compared to prior chip implementations, our design shows good hardware efficiency and is suitable for low-energy applications.

In Pursuit of a Connected Way of Knowing: The Case of One Mathematics Teacher

Science.gov (United States)

Agudelo-Valderrama, Cecilia; Martínez, Diana

2016-01-01

In this paper, we offer illustrations of a mathematics teacher's difficulties with content knowledge when trying to find connections between school mathematics and science; we do so by describing the development of this teacher's thinking and learning in her pursuit of connections between the concepts of slope of a line and density of matter. The…

In Pursuit of Internal Waves

Science.gov (United States)

Peacock, Thomas

2014-11-01

Orders of magnitude larger than surface waves, and so powerful that their generation impacts the lunar orbit, internal waves, propagating disturbances of a density-stratified fluid, are ubiquitous throughout the ocean and atmosphere. Following the discovery of the phenomenon of ``dead water'' by early Arctic explorers and the classic laboratory visualizations of the curious St. Andrew's Cross internal wave pattern, there has been a resurgence of interest in internal waves, inspired by their pivotal roles in local environmental and global climate processes, and their profound impact on ocean and aerospace engineering. We detail our widespread pursuit of internal waves through theoretical modeling, laboratory experiments and field studies, from the Pacific Ocean one thousand miles north and south of Hawaii, to the South China Sea, and on to the Arctic Ocean. We also describe our recent expedition to surf the most striking internal wave phenomenon of them all: the Morning Glory cloud in remote Northwest Australia. This work was supported by the National Science Foundation through a CAREER Grant OCE-064559 and through Grants OCE-1129757 and OCE-1357434, and by the Office of Naval Research through Grants N00014-09-1-0282, N00014-08-1-0390 and N00014-05-1-0575.

The Pursuit of Chronically Reliable Neural Interfaces: A Materials Perspective.

Science.gov (United States)

Guo, Liang

2016-01-01

Brain-computer interfaces represent one of the most astonishing technologies in our era. However, the grand challenge of chronic instability and limited throughput of the electrode-tissue interface has significantly hindered the further development and ultimate deployment of such exciting technologies. A multidisciplinary research workforce has been called upon to respond to this engineering need. In this paper, I briefly review this multidisciplinary pursuit of chronically reliable neural interfaces from a materials perspective by analyzing the problem, abstracting the engineering principles, and summarizing the corresponding engineering strategies. I further draw my future perspectives by extending the proposed engineering principles.

ALIGNMENT BETWEEN THE TYPES OF PROJECTS AND SKILLS PROJECT MANAGEMENT IN THE AES SUL DISTRIBUIDORA GAÚCHA DE ENERGIA S.A

Directory of Open Access Journals (Sweden)

Greice de Bem Noro

2011-10-01

Full Text Available The pursuit of excellence and new markets and customers has driven companies to build methods to reach goals and improve their strategies and competitive advantages. Therefore, the project management (PM has played a key role in the organizations to adjust deadlines, organizing methods and decision-making. Although many companies already use the PM as resource, this research attempt to contribute to increase the area trough the debate about alignment of companies projects types with the choice of the leader, in line with their skills. The study was developed in the AES Sul Distribuidora Gaúcha de Energia SA (AES Sul and examined how the alignment of the types of projects and management competencies can add value to the organization. The methodological procedure is classified as qualitative, quantitative and descriptive, conducted through a case study. The main results show the need for adjustments between the essential skills and AES Sul types of projects, beyond find some gaps regarding the leaders competencies.

Retro-regression--another important multivariate regression improvement.

Science.gov (United States)

Randić, M

2001-01-01

We review the serious problem associated with instabilities of the coefficients of regression equations, referred to as the MRA (multivariate regression analysis) "nightmare of the first kind". This is manifested when in a stepwise regression a descriptor is included or excluded from a regression. The consequence is an unpredictable change of the coefficients of the descriptors that remain in the regression equation. We follow with consideration of an even more serious problem, referred to as the MRA "nightmare of the second kind", arising when optimal descriptors are selected from a large pool of descriptors. This process typically causes at different steps of the stepwise regression a replacement of several previously used descriptors by new ones. We describe a procedure that resolves these difficulties. The approach is illustrated on boiling points of nonanes which are considered (1) by using an ordered connectivity basis; (2) by using an ordering resulting from application of greedy algorithm; and (3) by using an ordering derived from an exhaustive search for optimal descriptors. A novel variant of multiple regression analysis, called retro-regression (RR), is outlined showing how it resolves the ambiguities associated with both "nightmares" of the first and the second kind of MRA.

Modified Regression Correlation Coefficient for Poisson Regression Model

Science.gov (United States)

Kaengthong, Nattacha; Domthong, Uthumporn

2017-09-01

This study gives attention to indicators in predictive power of the Generalized Linear Model (GLM) which are widely used; however, often having some restrictions. We are interested in regression correlation coefficient for a Poisson regression model. This is a measure of predictive power, and defined by the relationship between the dependent variable (Y) and the expected value of the dependent variable given the independent variables [E(Y|X)] for the Poisson regression model. The dependent variable is distributed as Poisson. The purpose of this research was modifying regression correlation coefficient for Poisson regression model. We also compare the proposed modified regression correlation coefficient with the traditional regression correlation coefficient in the case of two or more independent variables, and having multicollinearity in independent variables. The result shows that the proposed regression correlation coefficient is better than the traditional regression correlation coefficient based on Bias and the Root Mean Square Error (RMSE).

A consensus successive projections algorithm--multiple linear regression method for analyzing near infrared spectra.

Science.gov (United States)

Liu, Ke; Chen, Xiaojing; Li, Limin; Chen, Huiling; Ruan, Xiukai; Liu, Wenbin

2015-02-09

The successive projections algorithm (SPA) is widely used to select variables for multiple linear regression (MLR) modeling. However, SPA used only once may not obtain all the useful information of the full spectra, because the number of selected variables cannot exceed the number of calibration samples in the SPA algorithm. Therefore, the SPA-MLR method risks the loss of useful information. To make a full use of the useful information in the spectra, a new method named "consensus SPA-MLR" (C-SPA-MLR) is proposed herein. This method is the combination of consensus strategy and SPA-MLR method. In the C-SPA-MLR method, SPA-MLR is used to construct member models with different subsets of variables, which are selected from the remaining variables iteratively. A consensus prediction is obtained by combining the predictions of the member models. The proposed method is evaluated by analyzing the near infrared (NIR) spectra of corn and diesel. The results of C-SPA-MLR method showed a better prediction performance compared with the SPA-MLR and full-spectra PLS methods. Moreover, these results could serve as a reference for combination the consensus strategy and other variable selection methods when analyzing NIR spectra and other spectroscopic techniques. Copyright © 2014 Elsevier B.V. All rights reserved.

Multiple predictor smoothing methods for sensitivity analysis.

Energy Technology Data Exchange (ETDEWEB)

Helton, Jon Craig; Storlie, Curtis B.

2006-08-01

The use of multiple predictor smoothing methods in sampling-based sensitivity analyses of complex models is investigated. Specifically, sensitivity analysis procedures based on smoothing methods employing the stepwise application of the following nonparametric regression techniques are described: (1) locally weighted regression (LOESS), (2) additive models, (3) projection pursuit regression, and (4) recursive partitioning regression. The indicated procedures are illustrated with both simple test problems and results from a performance assessment for a radioactive waste disposal facility (i.e., the Waste Isolation Pilot Plant). As shown by the example illustrations, the use of smoothing procedures based on nonparametric regression techniques can yield more informative sensitivity analysis results than can be obtained with more traditional sensitivity analysis procedures based on linear regression, rank regression or quadratic regression when nonlinear relationships between model inputs and model predictions are present.

Multiple predictor smoothing methods for sensitivity analysis

International Nuclear Information System (INIS)

Helton, Jon Craig; Storlie, Curtis B.

2006-01-01

The use of multiple predictor smoothing methods in sampling-based sensitivity analyses of complex models is investigated. Specifically, sensitivity analysis procedures based on smoothing methods employing the stepwise application of the following nonparametric regression techniques are described: (1) locally weighted regression (LOESS), (2) additive models, (3) projection pursuit regression, and (4) recursive partitioning regression. The indicated procedures are illustrated with both simple test problems and results from a performance assessment for a radioactive waste disposal facility (i.e., the Waste Isolation Pilot Plant). As shown by the example illustrations, the use of smoothing procedures based on nonparametric regression techniques can yield more informative sensitivity analysis results than can be obtained with more traditional sensitivity analysis procedures based on linear regression, rank regression or quadratic regression when nonlinear relationships between model inputs and model predictions are present

In Pursuit of Ethical Research: Studying Hybrid Communities Using Online and Face-to-Face Communications

Science.gov (United States)

Busher, Hugh; James, Nalita

2015-01-01

Hybrid communities using online and face-to-face communications to construct their practices are increasingly part of everyday life amongst people who have easy access to the internet. Researching these communities raises a number of challenges for researchers in the pursuit of ethical research. The paper begins by exploring what is understood by…

Applied software risk management a guide for software project managers

CERN Document Server

Pandian, C Ravindranath

2006-01-01

Few software projects are completed on time, on budget, and to their original specifications. Focusing on what practitioners need to know about risk in the pursuit of delivering software projects, Applied Software Risk Management: A Guide for Software Project Managers covers key components of the risk management process and the software development process, as well as best practices for software risk identification, risk planning, and risk analysis. Written in a clear and concise manner, this resource presents concepts and practical insight into managing risk. It first covers risk-driven project management, risk management processes, risk attributes, risk identification, and risk analysis. The book continues by examining responses to risk, the tracking and modeling of risks, intelligence gathering, and integrated risk management. It concludes with details on drafting and implementing procedures. A diary of a risk manager provides insight in implementing risk management processes.Bringing together concepts ...

Advanced Wind Turbine Program Next Generation Turbine Development Project: June 17, 1997--April 30, 2005

Energy Technology Data Exchange (ETDEWEB)

GE Wind Energy, LLC

2006-05-01

This document reports the technical results of the Next Generation Turbine Development Project conducted by GE Wind Energy LLC. This project is jointly funded by GE and the U.S. Department of Energy's National Renewable Energy Laboratory.The goal of this project is for DOE to assist the U.S. wind industry in exploring new concepts and applications of cutting-edge technology in pursuit of the specific objective of developing a wind turbine that can generate electricity at a levelized cost of energy of $0.025/kWh at sites with an average wind speed of 15 mph (at 10 m height).

Nonparametric instrumental regression with non-convex constraints

International Nuclear Information System (INIS)

Grasmair, M; Scherzer, O; Vanhems, A

2013-01-01

This paper considers the nonparametric regression model with an additive error that is dependent on the explanatory variables. As is common in empirical studies in epidemiology and economics, it also supposes that valid instrumental variables are observed. A classical example in microeconomics considers the consumer demand function as a function of the price of goods and the income, both variables often considered as endogenous. In this framework, the economic theory also imposes shape restrictions on the demand function, such as integrability conditions. Motivated by this illustration in microeconomics, we study an estimator of a nonparametric constrained regression function using instrumental variables by means of Tikhonov regularization. We derive rates of convergence for the regularized model both in a deterministic and stochastic setting under the assumption that the true regression function satisfies a projected source condition including, because of the non-convexity of the imposed constraints, an additional smallness condition. (paper)

Nonparametric instrumental regression with non-convex constraints

Science.gov (United States)

Grasmair, M.; Scherzer, O.; Vanhems, A.

2013-03-01

This paper considers the nonparametric regression model with an additive error that is dependent on the explanatory variables. As is common in empirical studies in epidemiology and economics, it also supposes that valid instrumental variables are observed. A classical example in microeconomics considers the consumer demand function as a function of the price of goods and the income, both variables often considered as endogenous. In this framework, the economic theory also imposes shape restrictions on the demand function, such as integrability conditions. Motivated by this illustration in microeconomics, we study an estimator of a nonparametric constrained regression function using instrumental variables by means of Tikhonov regularization. We derive rates of convergence for the regularized model both in a deterministic and stochastic setting under the assumption that the true regression function satisfies a projected source condition including, because of the non-convexity of the imposed constraints, an additional smallness condition.

Directional quantile regression in Octave (and MATLAB)

Czech Academy of Sciences Publication Activity Database

Boček, Pavel; Šiman, Miroslav

2016-01-01

Roč. 52, č. 1 (2016), s. 28-51 ISSN 0023-5954 R&D Projects: GA ČR GA14-07234S Institutional support: RVO:67985556 Keywords : quantile regression * multivariate quantile * depth contour * Matlab Subject RIV: IN - Informatics, Computer Science Impact factor: 0.379, year: 2016 http://library.utia.cas.cz/separaty/2016/SI/bocek-0458380.pdf

Dual Regression

OpenAIRE

Spady, Richard; Stouli, Sami

2012-01-01

We propose dual regression as an alternative to the quantile regression process for the global estimation of conditional distribution functions under minimal assumptions. Dual regression provides all the interpretational power of the quantile regression process while avoiding the need for repairing the intersecting conditional quantile surfaces that quantile regression often produces in practice. Our approach introduces a mathematical programming characterization of conditional distribution f...

Doppler distortion correction based on microphone array and matching pursuit algorithm for a wayside train bearing monitoring system

International Nuclear Information System (INIS)

Liu, Xingchen; Hu, Zhiyong; He, Qingbo; Zhang, Shangbin; Zhu, Jun

2017-01-01

Doppler distortion and background noise can reduce the effectiveness of wayside acoustic train bearing monitoring and fault diagnosis. This paper proposes a method of combining a microphone array and matching pursuit algorithm to overcome these difficulties. First, a dictionary is constructed based on the characteristics and mechanism of a far-field assumption. Then, the angle of arrival of the train bearing is acquired when applying matching pursuit to analyze the acoustic array signals. Finally, after obtaining the resampling time series, the Doppler distortion can be corrected, which is convenient for further diagnostic work. Compared with traditional single-microphone Doppler correction methods, the advantages of the presented array method are its robustness to background noise and its barely requiring pre-measuring parameters. Simulation and experimental study show that the proposed method is effective in performing wayside acoustic bearing fault diagnosis. (paper)

Doppler distortion correction based on microphone array and matching pursuit algorithm for a wayside train bearing monitoring system

Science.gov (United States)

Liu, Xingchen; Hu, Zhiyong; He, Qingbo; Zhang, Shangbin; Zhu, Jun

2017-10-01

Doppler distortion and background noise can reduce the effectiveness of wayside acoustic train bearing monitoring and fault diagnosis. This paper proposes a method of combining a microphone array and matching pursuit algorithm to overcome these difficulties. First, a dictionary is constructed based on the characteristics and mechanism of a far-field assumption. Then, the angle of arrival of the train bearing is acquired when applying matching pursuit to analyze the acoustic array signals. Finally, after obtaining the resampling time series, the Doppler distortion can be corrected, which is convenient for further diagnostic work. Compared with traditional single-microphone Doppler correction methods, the advantages of the presented array method are its robustness to background noise and its barely requiring pre-measuring parameters. Simulation and experimental study show that the proposed method is effective in performing wayside acoustic bearing fault diagnosis.

Multiple predictor smoothing methods for sensitivity analysis: Description of techniques

International Nuclear Information System (INIS)

Storlie, Curtis B.; Helton, Jon C.

2008-01-01

The use of multiple predictor smoothing methods in sampling-based sensitivity analyses of complex models is investigated. Specifically, sensitivity analysis procedures based on smoothing methods employing the stepwise application of the following nonparametric regression techniques are described: (i) locally weighted regression (LOESS), (ii) additive models, (iii) projection pursuit regression, and (iv) recursive partitioning regression. Then, in the second and concluding part of this presentation, the indicated procedures are illustrated with both simple test problems and results from a performance assessment for a radioactive waste disposal facility (i.e., the Waste Isolation Pilot Plant). As shown by the example illustrations, the use of smoothing procedures based on nonparametric regression techniques can yield more informative sensitivity analysis results than can be obtained with more traditional sensitivity analysis procedures based on linear regression, rank regression or quadratic regression when nonlinear relationships between model inputs and model predictions are present

In Pursuit of Reciprocity: Researchers, Teachers, and School Reformers Engaged in Collaborative Analysis of Video Records

Science.gov (United States)

Curry, Marnie W.

2012-01-01

In the ideal, reciprocity in qualitative inquiry occurs when there is give-and-take between researchers and the researched; however, the demands of the academy and resource constraints often make the pursuit of reciprocity difficult. Drawing on two video-based, qualitative studies in which researchers utilized video records as resources to enhance…

Effectiveness of educational and social worker interventions to activate patients' discussion and pursuit of preemptive living donor kidney transplantation: a randomized controlled trial.

Science.gov (United States)

Boulware, L Ebony; Hill-Briggs, Felicia; Kraus, Edward S; Melancon, J Keith; Falcone, Brenda; Ephraim, Patti L; Jaar, Bernard G; Gimenez, Luis; Choi, Michael; Senga, Mikiko; Kolotos, Maria; Lewis-Boyer, LaPricia; Cook, Courtney; Light, Laney; DePasquale, Nicole; Noletto, Todd; Powe, Neil R

2013-03-01

Many patients with chronic kidney disease (CKD) have difficulty becoming actively engaged in the pursuit of preemptive living donor kidney transplantation. The Talking About Live Kidney Donation (TALK) Study was a randomized controlled trial of the effectiveness of educational and social worker interventions designed to encourage early discussions and active pursuit of preemptive living donor kidney transplantation in patients with progressive CKD. We recruited participants with progressive CKD from academically affiliated nephrology practices in Baltimore, MD. Participants randomly received: (1) usual care (routine care with their nephrologists), the (2) TALK education intervention (video and booklet), or the (3) TALK social worker intervention (video and booklet plus patient and family social worker visits). We followed participants for 6 months to assess their self-reported achievement of behaviors reflecting their discussions about and/or pursuit of living donor kidney transplantation (discussions with family, discussions with physicians, initiating recipient evaluation, completing recipient evaluation, and identifying a potential living donor). We assessed outcomes through a questionnaire at 1-, 3-, and 6-months follow-up. Participants receiving usual care with their nephrologists (n = 44), TALK education (n = 43), and the TALK social worker (n = 43) were similar at baseline. TALK Study interventions improved participants' living donor kidney transplantation discussion and pursuit behaviors, with the social worker leading to greater patient activation (participants' predicted probability of achieving living donor kidney transplantation discussions, evaluations, or donor identification over 6 months): probabilities were 30% (95% CI, 20%-46%), 42% (95% CI, 33%-54%), and 58% (95% CI, 41%-83%), respectively, in the usual care, TALK education, and TALK social worker groups (P = 0.03). Our population was well educated and mostly insured, potentially limiting

Time-Frequency Data Reduction for Event Related Potentials: Combining Principal Component Analysis and Matching Pursuit

Directory of Open Access Journals (Sweden)

Selin Aviyente

2010-01-01

Full Text Available Joint time-frequency representations offer a rich representation of event related potentials (ERPs that cannot be obtained through individual time or frequency domain analysis. This representation, however, comes at the expense of increased data volume and the difficulty of interpreting the resulting representations. Therefore, methods that can reduce the large amount of time-frequency data to experimentally relevant components are essential. In this paper, we present a method that reduces the large volume of ERP time-frequency data into a few significant time-frequency parameters. The proposed method is based on applying the widely used matching pursuit (MP approach, with a Gabor dictionary, to principal components extracted from the time-frequency domain. The proposed PCA-Gabor decomposition is compared with other time-frequency data reduction methods such as the time-frequency PCA approach alone and standard matching pursuit methods using a Gabor dictionary for both simulated and biological data. The results show that the proposed PCA-Gabor approach performs better than either the PCA alone or the standard MP data reduction methods, by using the smallest amount of ERP data variance to produce the strongest statistical separation between experimental conditions.

Parametric vs. Nonparametric Regression Modelling within Clinical Decision Support

Czech Academy of Sciences Publication Activity Database

Kalina, Jan; Zvárová, Jana

2017-01-01

Roč. 5, č. 1 (2017), s. 21-27 ISSN 1805-8698 R&D Projects: GA ČR GA17-01251S Institutional support: RVO:67985807 Keywords : decision support systems * decision rules * statistical analysis * nonparametric regression Subject RIV: IN - Informatics, Computer Science OBOR OECD: Statistics and probability

Multicollinearity is a red herring in the search for moderator variables: A guide to interpreting moderated multiple regression models and a critique of Iacobucci, Schneider, Popovich, and Bakamitsos (2016).

Science.gov (United States)

McClelland, Gary H; Irwin, Julie R; Disatnik, David; Sivan, Liron

2017-02-01

Multicollinearity is irrelevant to the search for moderator variables, contrary to the implications of Iacobucci, Schneider, Popovich, and Bakamitsos (Behavior Research Methods, 2016, this issue). Multicollinearity is like the red herring in a mystery novel that distracts the statistical detective from the pursuit of a true moderator relationship. We show multicollinearity is completely irrelevant for tests of moderator variables. Furthermore, readers of Iacobucci et al. might be confused by a number of their errors. We note those errors, but more positively, we describe a variety of methods researchers might use to test and interpret their moderated multiple regression models, including two-stage testing, mean-centering, spotlighting, orthogonalizing, and floodlighting without regard to putative issues of multicollinearity. We cite a number of recent studies in the psychological literature in which the researchers used these methods appropriately to test, to interpret, and to report their moderated multiple regression models. We conclude with a set of recommendations for the analysis and reporting of moderated multiple regression that should help researchers better understand their models and facilitate generalizations across studies.

Support agnostic Bayesian matching pursuit for block sparse signals

KAUST Repository

Masood, Mudassir

2013-05-01

A fast matching pursuit method using a Bayesian approach is introduced for block-sparse signal recovery. This method performs Bayesian estimates of block-sparse signals even when the distribution of active blocks is non-Gaussian or unknown. It is agnostic to the distribution of active blocks in the signal and utilizes a priori statistics of additive noise and the sparsity rate of the signal, which are shown to be easily estimated from data and no user intervention is required. The method requires a priori knowledge of block partition and utilizes a greedy approach and order-recursive updates of its metrics to find the most dominant sparse supports to determine the approximate minimum mean square error (MMSE) estimate of the block-sparse signal. Simulation results demonstrate the power and robustness of our proposed estimator. © 2013 IEEE.

Users manual. Pursuit program of use licenses of radioactive material or generator equipment of ionizing radiations

International Nuclear Information System (INIS)

Becerril M, V.M.; Villarreal, J.E.

1992-05-01

The objective of the program 'Databases for the pursuit of licenses of use of radioactive material', it consists on the application of a computer system carried out in dbase IV that it allows the control of the all the information related with those licenses for use, possession and storage of radioactive material or generator equipment of ionizing radiations. (Author)

Regression: A Bibliography.

Science.gov (United States)

Pedrini, D. T.; Pedrini, Bonnie C.

Regression, another mechanism studied by Sigmund Freud, has had much research, e.g., hypnotic regression, frustration regression, schizophrenic regression, and infra-human-animal regression (often directly related to fixation). Many investigators worked with hypnotic age regression, which has a long history, going back to Russian reflexologists.…

Multitask Quantile Regression under the Transnormal Model.

Science.gov (United States)

Fan, Jianqing; Xue, Lingzhou; Zou, Hui

2016-01-01

We consider estimating multi-task quantile regression under the transnormal model, with focus on high-dimensional setting. We derive a surprisingly simple closed-form solution through rank-based covariance regularization. In particular, we propose the rank-based ℓ 1 penalization with positive definite constraints for estimating sparse covariance matrices, and the rank-based banded Cholesky decomposition regularization for estimating banded precision matrices. By taking advantage of alternating direction method of multipliers, nearest correlation matrix projection is introduced that inherits sampling properties of the unprojected one. Our work combines strengths of quantile regression and rank-based covariance regularization to simultaneously deal with nonlinearity and nonnormality for high-dimensional regression. Furthermore, the proposed method strikes a good balance between robustness and efficiency, achieves the "oracle"-like convergence rate, and provides the provable prediction interval under the high-dimensional setting. The finite-sample performance of the proposed method is also examined. The performance of our proposed rank-based method is demonstrated in a real application to analyze the protein mass spectroscopy data.

Users manual for the pursuit of the radiological status of the nuclear and radioactive facilities of the ININ

International Nuclear Information System (INIS)

Sotelo B, D.; Villarreal, J.E.

1992-05-01

The purpose of this program consists on a database that gives pursuit at the radiation levels in laboratories and facilities users of radioactive material or generators of ionizing radiations, introducing in it mensurations that were made in different departments, for its later analysis. (Author)

Culturally appropriate organization of water and sewerage projects built through public private partnerships.

Directory of Open Access Journals (Sweden)

Jessica A Kaminsky

Full Text Available This paper contributes to the pursuit of socially sustainable water and sanitation infrastructure for all people by discovering statistically robust relationships between Hofstede's dimensions of cross-cultural comparison and the choice of contract award types, project type, and primary revenue sources. This analysis, which represents 973 projects distributed across 24 low- and middle-income nations, uses a World Bank dataset describing high capital cost water and sewerage projects funded through private investment. The results show that cultural dimensions explain variation in the choice of contract award types, project type, and primary revenue sources. These results provide empirical evidence that strategies for water and sewerage project organization are not culturally neutral. The data show, for example, that highly individualistic contexts are more likely to select competitive contract award types and to depend on user fees to provide the primary project revenue stream post-construction. By selecting more locally appropriate ways to organize projects, project stakeholders will be better able to pursue the construction of socially sustainable water and sewerage infrastructure.

Culturally appropriate organization of water and sewerage projects built through public private partnerships.

Science.gov (United States)

Kaminsky, Jessica A

2017-01-01

This paper contributes to the pursuit of socially sustainable water and sanitation infrastructure for all people by discovering statistically robust relationships between Hofstede's dimensions of cross-cultural comparison and the choice of contract award types, project type, and primary revenue sources. This analysis, which represents 973 projects distributed across 24 low- and middle-income nations, uses a World Bank dataset describing high capital cost water and sewerage projects funded through private investment. The results show that cultural dimensions explain variation in the choice of contract award types, project type, and primary revenue sources. These results provide empirical evidence that strategies for water and sewerage project organization are not culturally neutral. The data show, for example, that highly individualistic contexts are more likely to select competitive contract award types and to depend on user fees to provide the primary project revenue stream post-construction. By selecting more locally appropriate ways to organize projects, project stakeholders will be better able to pursue the construction of socially sustainable water and sewerage infrastructure.

Current Mathematical Methods Used in QSAR/QSPR Studies

Directory of Open Access Journals (Sweden)

Peixun Liu

2009-04-01

Full Text Available This paper gives an overview of the mathematical methods currently used in quantitative structure-activity/property relationship (QASR/QSPR studies. Recently, the mathematical methods applied to the regression of QASR/QSPR models are developing very fast, and new methods, such as Gene Expression Programming (GEP, Project Pursuit Regression (PPR and Local Lazy Regression (LLR have appeared on the QASR/QSPR stage. At the same time, the earlier methods, including Multiple Linear Regression (MLR, Partial Least Squares (PLS, Neural Networks (NN, Support Vector Machine (SVM and so on, are being upgraded to improve their performance in QASR/QSPR studies. These new and upgraded methods and algorithms are described in detail, and their advantages and disadvantages are evaluated and discussed, to show their application potential in QASR/QSPR studies in the future.

Projected regression method for solving Fredholm integral equations arising in the analytic continuation problem of quantum physics

International Nuclear Information System (INIS)

Arsenault, Louis-François; Millis, Andrew J; Neuberg, Richard; Hannah, Lauren A

2017-01-01

We present a supervised machine learning approach to the inversion of Fredholm integrals of the first kind as they arise, for example, in the analytic continuation problem of quantum many-body physics. The approach provides a natural regularization for the ill-conditioned inverse of the Fredholm kernel, as well as an efficient and stable treatment of constraints. The key observation is that the stability of the forward problem permits the construction of a large database of outputs for physically meaningful inputs. Applying machine learning to this database generates a regression function of controlled complexity, which returns approximate solutions for previously unseen inputs; the approximate solutions are then projected onto the subspace of functions satisfying relevant constraints. Under standard error metrics the method performs as well or better than the Maximum Entropy method for low input noise and is substantially more robust to increased input noise. We suggest that the methodology will be similarly effective for other problems involving a formally ill-conditioned inversion of an integral operator, provided that the forward problem can be efficiently solved. (paper)

Advanced statistics: linear regression, part I: simple linear regression.

Science.gov (United States)

Marill, Keith A

2004-01-01

Simple linear regression is a mathematical technique used to model the relationship between a single independent predictor variable and a single dependent outcome variable. In this, the first of a two-part series exploring concepts in linear regression analysis, the four fundamental assumptions and the mechanics of simple linear regression are reviewed. The most common technique used to derive the regression line, the method of least squares, is described. The reader will be acquainted with other important concepts in simple linear regression, including: variable transformations, dummy variables, relationship to inference testing, and leverage. Simplified clinical examples with small datasets and graphic models are used to illustrate the points. This will provide a foundation for the second article in this series: a discussion of multiple linear regression, in which there are multiple predictor variables.

IS-ENES project management - lessons learnt

Science.gov (United States)

Parinet, Marie; Guglielmo, Francesca; Joussaume, Sylvie

2017-04-01

IS-ENES is the distributed e-infrastructure of models, model data and metadata of the European Network for Earth System Modelling (ENES). It has benefitted from two EC FP7 grants and aims towards further European and national funding to achieve sustainability. We highlight here several challenges related to project management that have risen in the course of these two project-phases spanning 8 years. Some challenges are related to the heterogeneity of the activities within IS-ENES, with different groups working on very diverse activities, not necessarily strictly interdependent. An immediate consequence is the need of implementing and setting up in early phases of the project efficient collection and circulation of information to preserve and reinforce the systemic view of the infrastructure as a whole and the pursuit of common goals, including coordinated provision of services. Toward and beyond such common goals, managing IS-ENES, covering both scientific and more strictly management-related aspects, implies a double-paced approach: besides setting up efficient project workflow, there is the need of setting up longer term objectives. This implies, within the project lifetime, to elaborate and implement a coherent organizational (consistent with scientific goals, funding schemes, research and technology landscape) strategy to pursue these goals beyond the project itself. Furthermore, a series of more generic project management challenges will also be listed and can be gathered around 3 main objectives: ease the internal processes in order to optimize the work, anticipate delays and budget issues, and motivate the project teams by ensuring an efficient internal and external communication.

Multiple predictor smoothing methods for sensitivity analysis: Example results

International Nuclear Information System (INIS)

Storlie, Curtis B.; Helton, Jon C.

2008-01-01

The use of multiple predictor smoothing methods in sampling-based sensitivity analyses of complex models is investigated. Specifically, sensitivity analysis procedures based on smoothing methods employing the stepwise application of the following nonparametric regression techniques are described in the first part of this presentation: (i) locally weighted regression (LOESS), (ii) additive models, (iii) projection pursuit regression, and (iv) recursive partitioning regression. In this, the second and concluding part of the presentation, the indicated procedures are illustrated with both simple test problems and results from a performance assessment for a radioactive waste disposal facility (i.e., the Waste Isolation Pilot Plant). As shown by the example illustrations, the use of smoothing procedures based on nonparametric regression techniques can yield more informative sensitivity analysis results than can be obtained with more traditional sensitivity analysis procedures based on linear regression, rank regression or quadratic regression when nonlinear relationships between model inputs and model predictions are present

Accelerometer measured daily physical activity and sedentary pursuits--comparison between two models of the Actigraph and the importance of data reduction.

Science.gov (United States)

Tanha, Tina; Tornberg, Åsa; Dencker, Magnus; Wollmer, Per

2013-10-31

Very few validation studies have been performed between different generations of the commonly used Actigraph accelerometers. We compared daily physical activity data generated from the old generation Actigraph model 7164 with the new generation Actigraph GT1M accelerometer in 15 young females for eight consecutive days. We also investigated if different wear time thresholds had any impact on the findings. Minutes per day of moderate and vigorous physical activity (MVPA), vigorous physical activity (VPA) and very vigorous physical activity (VVPA) were calculated. Moreover, minutes of sedentary pursuits per day were calculated. There were significant (P physical activity. Median minutes of sedentary pursuits per day are highly dependent on which wear time threshold that is used, and not by accelerometer model.

Nostalgia motivates pursuit of important goals by increasing meaning in life

DEFF Research Database (Denmark)

Sedikides, Constantine; Cheung, Wing-Yee; Wildschut, Tim

2018-01-01

This research focused on existential and motivational implications of the emotion of nostalgia. Nostalgia (relative to control) increased meaning in life, which, in turn, galvanised intentions to pursue one's most important goal (Experiment 1) and to pursue one's most important, but not least...... in life. Also, this is the first evidence that meaning is associated with specific motivational consequences. Discussion considers the relevance of the findings for the emotion and motivation literatures....... important, goal (Experiment 2). The basic pattern held in two cultures (British and Danish) independently of positive affect. This is the first evidence that nostalgia has specific motivational consequences (i.e., pursuit of more, but not less, important goals) and transmits these consequences via meaning...

A high-resolution processing technique for improving the energy of weak signal based on matching pursuit

Directory of Open Access Journals (Sweden)

Shuyan Wang

2016-05-01

Full Text Available This paper proposes a new method to improve the resolution of the seismic signal and to compensate the energy of weak seismic signal based on matching pursuit. With a dictionary of Morlet wavelets, matching pursuit algorithm can decompose a seismic trace into a series of wavelets. We abstract complex-trace attributes from analytical expressions to shrink the search range of amplitude, frequency and phase. In addition, considering the level of correlation between constituent wavelets and average wavelet abstracted from well-seismic calibration, we can obtain the search range of scale which is an important adaptive parameter to control the width of wavelet in time and the bandwidth of frequency. Hence, the efficiency of selection of proper wavelets is improved by making first a preliminary estimate and refining a local selecting range. After removal of noise wavelets, we integrate useful wavelets which should be firstly executed by adaptive spectral whitening technique. This approach can improve the resolutions of seismic signal and enhance the energy of weak wavelets simultaneously. The application results of real seismic data show this method has a good perspective of application.

Gender and the Dark Side of the Border in Laila Lalami’s Hope and other Dangerous Pursuits

Directory of Open Access Journals (Sweden)

Kareem Al-Jayikh Ali

2016-12-01

Full Text Available Starting from Arab-American women’s narratives, this study explores to what extent hegemonic history excludes and silences female Arab bodies and their relation to sexuality. It will also address the issue of present day migration, as reflected by Moroccan-American author Laila Lalami in her novel Hope and Other Dangerous Pursuits (2005.

Semiparametric nonlinear quantile regression model for financial returns

Czech Academy of Sciences Publication Activity Database

Avdulaj, Krenar; Baruník, Jozef

2017-01-01

Roč. 21, č. 1 (2017), s. 81-97 ISSN 1081-1826 R&D Projects: GA ČR(CZ) GBP402/12/G097 Institutional support: RVO:67985556 Keywords : copula quantile regression * realized volatility * value-at-risk Subject RIV: AH - Economic s OBOR OECD: Applied Economic s, Econometrics Impact factor: 0.649, year: 2016 http://library.utia.cas.cz/separaty/2017/E/avdulaj-0472346.pdf

On-line mixture-based alternative to logistic regression

Czech Academy of Sciences Publication Activity Database

Nagy, Ivan; Suzdaleva, Evgenia

2016-01-01

Roč. 26, č. 5 (2016), s. 417-437 ISSN 1210-0552 R&D Projects: GA ČR GA15-03564S Institutional support: RVO:67985556 Keywords : on-line modeling * on-line logistic regression * recursive mixture estimation * data dependent pointer Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.394, year: 2016 http://library.utia.cas.cz/separaty/2016/ZS/suzdaleva-0464463.pdf

Ordinary least square regression, orthogonal regression, geometric mean regression and their applications in aerosol science

International Nuclear Information System (INIS)

Leng Ling; Zhang Tianyi; Kleinman, Lawrence; Zhu Wei

2007-01-01

Regression analysis, especially the ordinary least squares method which assumes that errors are confined to the dependent variable, has seen a fair share of its applications in aerosol science. The ordinary least squares approach, however, could be problematic due to the fact that atmospheric data often does not lend itself to calling one variable independent and the other dependent. Errors often exist for both measurements. In this work, we examine two regression approaches available to accommodate this situation. They are orthogonal regression and geometric mean regression. Comparisons are made theoretically as well as numerically through an aerosol study examining whether the ratio of organic aerosol to CO would change with age

Polynomial regression analysis and significance test of the regression function

International Nuclear Information System (INIS)

Gao Zhengming; Zhao Juan; He Shengping

2012-01-01

In order to analyze the decay heating power of a certain radioactive isotope per kilogram with polynomial regression method, the paper firstly demonstrated the broad usage of polynomial function and deduced its parameters with ordinary least squares estimate. Then significance test method of polynomial regression function is derived considering the similarity between the polynomial regression model and the multivariable linear regression model. Finally, polynomial regression analysis and significance test of the polynomial function are done to the decay heating power of the iso tope per kilogram in accord with the authors' real work. (authors)

Regression periods in infancy: a case study from Catalonia.

Science.gov (United States)

Sadurní, Marta; Rostan, Carlos

2002-05-01

Based on Rijt-Plooij and Plooij's (1992) research on emergence of regression periods in the first two years of life, the presence of such periods in a group of 18 babies (10 boys and 8 girls, aged between 3 weeks and 14 months) from a Catalonian population was analyzed. The measurements were a questionnaire filled in by the infants' mothers, a semi-structured weekly tape-recorded interview, and observations in their homes. The procedure and the instruments used in the project follow those proposed by Rijt-Plooij and Plooij. Our results confirm the existence of the regression periods in the first year of children's life. Inter-coder agreement for trained coders was 78.2% and within-coder agreement was 90.1%. In the discussion, the possible meaning and relevance of regression periods in order to understand development from a psychobiological and social framework is commented upon.

Reduced Rank Regression

DEFF Research Database (Denmark)

Johansen, Søren

2008-01-01

The reduced rank regression model is a multivariate regression model with a coefficient matrix with reduced rank. The reduced rank regression algorithm is an estimation procedure, which estimates the reduced rank regression model. It is related to canonical correlations and involves calculating...

Motivational pursuits in the context of human sexual relationships.

Science.gov (United States)

Cooper, M Lynne; Barber, Lindsay L; Zhaoyang, Ruixue; Talley, Amelia E

2011-12-01

The current article examines how close relationships combine with individual differences in sex motives (Cooper, Shapiro, & Powers, 1998) to shape sexual experience. We first provide an overview of the motivational approach as it relates to sexual behavior and then describe 2 broad mechanisms (1 transactional, the other interactional) by which motives and relational context combine to shape behavior. Drawing on our past research, we review evidence showing that people select relationship contexts based partly on their motives and that these contexts in turn shape future motives and behavior; that partner motives shape sexual experience above and beyond one's own motives; and that both the broader relationship context and partner motives moderate the effects of one's own motives on sexual experience. We conclude that the nature of motivational pursuits cannot be adequately understood in the abstract, but rather we must take into account the relational context in which one's needs are pursued. © 2010 The Authors. Journal of Personality © 2011, Wiley Periodicals, Inc.

Future Projection with an Extreme-Learning Machine and Support Vector Regression of Reference Evapotranspiration in a Mountainous Inland Watershed in North-West China

Directory of Open Access Journals (Sweden)

Zhenliang Yin

2017-11-01

Full Text Available This study aims to project future variability of reference evapotranspiration (ET0 using artificial intelligence methods, constructed with an extreme-learning machine (ELM and support vector regression (SVR in a mountainous inland watershed in north-west China. Eight global climate model (GCM outputs retrieved from the Coupled Model Inter-comparison Project Phase 5 (CMIP5 were employed to downscale monthly ET0 for the historical period 1960–2005 as a validation approach and for the future period 2010–2099 as a projection of ET0 under the Representative Concentration Pathway (RCP 4.5 and 8.5 scenarios. The following conclusions can be drawn: the ELM and SVR methods demonstrate a very good performance in estimating Food and Agriculture Organization (FAO-56 Penman–Monteith ET0. Variation in future ET0 mainly occurs in the spring and autumn seasons, while the summer and winter ET0 changes are moderately small. Annually, the ET0 values were shown to increase at a rate of approximately 7.5 mm, 7.5 mm, 0.0 mm (8.2 mm, 15.0 mm, 15.0 mm decade−1, respectively, for the near-term projection (2010–2039, mid-term projection (2040–2069, and long-term projection (2070–2099 under the RCP4.5 (RCP8.5 scenario. Compared to the historical period, the relative changes in ET0 were found to be approximately 2%, 5% and 6% (2%, 7% and 13%, during the near, mid- and long-term periods, respectively, under the RCP4.5 (RCP8.5 warming scenarios. In accordance with the analyses, we aver that the opportunity to downscale monthly ET0 with artificial intelligence is useful in practice for water-management policies.

Quantile Regression Methods

DEFF Research Database (Denmark)

Fitzenberger, Bernd; Wilke, Ralf Andreas

2015-01-01

if the mean regression model does not. We provide a short informal introduction into the principle of quantile regression which includes an illustrative application from empirical labor market research. This is followed by briefly sketching the underlying statistical model for linear quantile regression based......Quantile regression is emerging as a popular statistical approach, which complements the estimation of conditional mean models. While the latter only focuses on one aspect of the conditional distribution of the dependent variable, the mean, quantile regression provides more detailed insights...... by modeling conditional quantiles. Quantile regression can therefore detect whether the partial effect of a regressor on the conditional quantiles is the same for all quantiles or differs across quantiles. Quantile regression can provide evidence for a statistical relationship between two variables even...

Hypochondriasis and somatization in college women: a personal projects analysis.

Science.gov (United States)

Karoly, P; Lecci, L

1993-03-01

Although the descriptive features of hypochondriasis and somatization have been widely studied, the motivational correlates (goal representations) of individuals manifesting abnormal illness patterns have not been considered. The Personal Projects Analysis method (Little, 1983) was used to contrast the health and nonhealth goals of female undergraduates. Subjects selected 10 goals for evaluation along a series of dimensions. When health pursuits alone were examined, hypochondriasis on the Minnesota Multiphasic Personality Inventory was found to correlate directly with goal appraisal dimensions subsumed by an anxiety-absorption factor and inversely with dimensions characterizing rewardingness, thus suggesting a negativity of health goal construal. Somatizers also pursued more health-related projects than did nonsomatizers; nonhealth goal cognition did not relate as strongly to hypochondriasis. Finally, using discriminant function analysis, goal representations were shown to significantly and substantially differentiate somatizers from nonsomatizers.

Estimating Required Contingency Funds for Construction Projects using Multiple Linear Regression

National Research Council Canada - National Science Library

Cook, Jason J

2006-01-01

Cost overruns are a critical problem for construction projects. The common practice for dealing with cost overruns is the assignment of an arbitrary flat percentage of the construction budget as a contingency fund...

Increased Saccadic Rate during Smooth Pursuit Eye Movements in Patients at Ultra High Risk for Developing a Psychosis

Science.gov (United States)

van Tricht, M. J.; Nieman, D. H.; Bour, L. J.; Boeree, T.; Koelman, J. H. T. M.; de Haan, L.; Linszen, D. H.

2010-01-01

Abnormalities in eye tracking are consistently observed in schizophrenia patients and their relatives and have been proposed as an endophenotype of the disease. The aim of this study was to investigate the performance of patients at Ultra High Risk (UHR) for developing psychosis on a task of smooth pursuit eye movement (SPEM). Forty-six UHR…

A Monte Carlo simulation study comparing linear regression, beta regression, variable-dispersion beta regression and fractional logit regression at recovering average difference measures in a two sample design.

Science.gov (United States)

Meaney, Christopher; Moineddin, Rahim

2014-01-24

In biomedical research, response variables are often encountered which have bounded support on the open unit interval--(0,1). Traditionally, researchers have attempted to estimate covariate effects on these types of response data using linear regression. Alternative modelling strategies may include: beta regression, variable-dispersion beta regression, and fractional logit regression models. This study employs a Monte Carlo simulation design to compare the statistical properties of the linear regression model to that of the more novel beta regression, variable-dispersion beta regression, and fractional logit regression models. In the Monte Carlo experiment we assume a simple two sample design. We assume observations are realizations of independent draws from their respective probability models. The randomly simulated draws from the various probability models are chosen to emulate average proportion/percentage/rate differences of pre-specified magnitudes. Following simulation of the experimental data we estimate average proportion/percentage/rate differences. We compare the estimators in terms of bias, variance, type-1 error and power. Estimates of Monte Carlo error associated with these quantities are provided. If response data are beta distributed with constant dispersion parameters across the two samples, then all models are unbiased and have reasonable type-1 error rates and power profiles. If the response data in the two samples have different dispersion parameters, then the simple beta regression model is biased. When the sample size is small (N0 = N1 = 25) linear regression has superior type-1 error rates compared to the other models. Small sample type-1 error rates can be improved in beta regression models using bias correction/reduction methods. In the power experiments, variable-dispersion beta regression and fractional logit regression models have slightly elevated power compared to linear regression models. Similar results were observed if the

Detection of Differential Item Functioning with Nonlinear Regression: A Non-IRT Approach Accounting for Guessing

Czech Academy of Sciences Publication Activity Database

Drabinová, Adéla; Martinková, Patrícia

2017-01-01

Roč. 54, č. 4 (2017), s. 498-517 ISSN 0022-0655 R&D Projects: GA ČR GJ15-15856Y Institutional support: RVO:67985807 Keywords : differential item functioning * non-linear regression * logistic regression * item response theory Subject RIV: AM - Education OBOR OECD: Statistics and probability Impact factor: 0.979, year: 2016

Generic project definitions for improvement of health care delivery: a case-based approach.

Science.gov (United States)

Niemeijer, Gerard C; Does, Ronald J M M; de Mast, Jeroen; Trip, Albert; van den Heuvel, Jaap

2011-01-01

The purpose of this article is to create actionable knowledge, making the definition of process improvement projects in health care delivery more effective. This study is a retrospective analysis of process improvement projects in hospitals, facilitating a case-based reasoning approach to project definition. Data sources were project documentation and hospital-performance statistics of 271 Lean Six Sigma health care projects from 2002 to 2009 of general, teaching, and academic hospitals in the Netherlands and Belgium. Objectives and operational definitions of improvement projects in the sample, analyzed and structured in a uniform format and terminology. Extraction of reusable elements of earlier project definitions, presented in the form of 9 templates called generic project definitions. These templates function as exemplars for future process improvement projects, making the selection, definition, and operationalization of similar projects more efficient. Each template includes an explicated rationale, an operationalization in the form of metrics, and a prototypical example. Thus, a process of incremental and sustained learning based on case-based reasoning is facilitated. The quality of project definitions is a crucial success factor in pursuits to improve health care delivery. We offer 9 tried and tested improvement themes related to patient safety, patient satisfaction, and business-economic performance of hospitals.

Pedagogical design for knowledge creating inquiry in customer projects

Directory of Open Access Journals (Sweden)

Hanni Muukkonen

2013-09-01

Full Text Available Two higher education courses involving students, teachers, and customers in multifaceted experiences of knowledge creation are described. The Trialogical Learning Approach (TLA provides a theoretical framework to address learning and teaching organized around authentic problems and the development of shared knowledge objects, such as reports, products, and new practices. The approach directs attention to those aspects of social interaction and artifact-mediated activities, which focus on the development of shared objects and the pursuit of novel knowledge and understanding. The roles of technology-mediation, customer involvement, and guidance in developing effective pedagogical practices for knowledge creation were addressed. It appears necessary to design sufficient open-endedness and complexity for students’ teamwork to generate unpredictable, practical, and epistemologically challenging situations. Pedagogical design for such a process has different foci in the four central phases: planning, project initiation, project execution, and presentation and evaluation. Planning and initiation are central to establishing relevance and project awareness for the collaboration of student teams with a customer. Guidance and expert modeling during project initiation and execution is needed to overcome feelings of uncertainty during a challenging and complex assignment. Mediation provided by collaboration tools facilitates reflection on collective practices, iterative development of knowledge objects, and documentation of the learning outcomes of customer projects.

Regression Phalanxes

OpenAIRE

Zhang, Hongyang; Welch, William J.; Zamar, Ruben H.

2017-01-01

Tomal et al. (2015) introduced the notion of "phalanxes" in the context of rare-class detection in two-class classification problems. A phalanx is a subset of features that work well for classification tasks. In this paper, we propose a different class of phalanxes for application in regression settings. We define a "Regression Phalanx" - a subset of features that work well together for prediction. We propose a novel algorithm which automatically chooses Regression Phalanxes from high-dimensi...

Tumour Progression and Spontaneous Regression in the Lewis Rat Sarcoma Model

Czech Academy of Sciences Publication Activity Database

Kovalská, Jana; Mishra, Rajbardhan; Jebavý, L.; Makovický, P.; Janda, Jozef; Plánská, D.; Červinková, Monika; Horák, Vratislav

2015-01-01

Roč. 35, č. 12 (2015), s. 6539-6549 ISSN 0250-7005 R&D Projects: GA MŠk ED2.1.00/03.0124 Institutional support: RVO:67985904 Keywords : spontaneous regression * progression * sarcoma Subject RIV: FD - Oncology ; Hematology Impact factor: 1.895, year: 2015

Eleventh Annual "Brown" Lecture in Education Research A Long Shadow: The American Pursuit of Political Justice and Education Equality

Science.gov (United States)

Anderson, James D.

2015-01-01

This article examines the historical relationship between political power and the pursuit of education and social equality from the Reconstruction era to the present. The chief argument is that education equality is historically linked to and even predicated on equal political power, specifically, equal access to the franchise and instruments of…

Integrated detection, estimation, and guidance in pursuit of a maneuvering target

Science.gov (United States)

Dionne, Dany

The thesis focuses on efficient solutions of non-cooperative pursuit-evasion games with imperfect information on the state of the system. This problem is important in the context of interception of future maneuverable ballistic missiles. However, the theoretical developments are expected to find application to a broad class of hybrid control and estimation problems in industry. The validity of the results is nevertheless confirmed using a benchmark problem in the area of terminal guidance. A specific interception scenario between an incoming target with no information and a single interceptor missile with noisy measurements is analyzed in the form of a linear hybrid system subject to additive abrupt changes. The general research is aimed to achieve improved homing accuracy by integrating ideas from detection theory, state estimation theory and guidance. The results achieved can be summarized as follows. (i) Two novel maneuver detectors are developed to diagnose abrupt changes in a class of hybrid systems (detection and isolation of evasive maneuvers): a new implementation of the GLR detector and the novel adaptive- H0 GLR detector. (ii) Two novel state estimators for target tracking are derived using the novel maneuver detectors. The state estimators employ parameterized family of functions to described possible evasive maneuvers. (iii) A novel adaptive Bayesian multiple model predictor of the ballistic miss is developed which employs semi-Markov models and ideas from detection theory. (iv) A novel integrated estimation and guidance scheme that significantly improves the homing accuracy is also presented. The integrated scheme employs banks of estimators and guidance laws, a maneuver detector, and an on-line governor; the scheme is adaptive with respect to the uncertainty affecting the probability density function of the filtered state. (v) A novel discretization technique for the family of continuous-time, game theoretic, bang-bang guidance laws is introduced. The

A method for evaluating the funding of components of natural resource and conservation projects

International Nuclear Information System (INIS)

Wellington, John F.; Lewis, Stephen A.

2016-01-01

Many public and private entities such as government agencies and private foundations have missions related to the improvement, protection, and sustainability of the environment. In pursuit of their missions, they fund projects with related outcomes. Typically, the funding scene consists of scarce funding dollars for the many project requests. In light of funding limitations and funder's search for innovative funding schemes, a method to support the allocation of scarce dollars among project components is presented. The proposed scheme has similarities to methods in the project selection literature but differs in its focus on project components and its connection to and enumeration of the universe of funding possibilities. The value of having access to the universe is demonstrated with illustrations. The presentation includes Excel implementations that should appeal to a broad spectrum of project evaluators and reviewers. Access to the space of funding possibilities facilitates a rich analysis of funding alternatives. - Highlights: • Method is given for allocating scarce funding dollars among competing projects. • Allocations are made to fund parts of projects • Proposed method provides access to the universe of funding possibilities. • Proposed method facilitates a rich analysis of funding possibilities. • Excel spreadsheet implementations are provided

Advanced statistics: linear regression, part II: multiple linear regression.

Science.gov (United States)

Marill, Keith A

2004-01-01

The applications of simple linear regression in medical research are limited, because in most situations, there are multiple relevant predictor variables. Univariate statistical techniques such as simple linear regression use a single predictor variable, and they often may be mathematically correct but clinically misleading. Multiple linear regression is a mathematical technique used to model the relationship between multiple independent predictor variables and a single dependent outcome variable. It is used in medical research to model observational data, as well as in diagnostic and therapeutic studies in which the outcome is dependent on more than one factor. Although the technique generally is limited to data that can be expressed with a linear function, it benefits from a well-developed mathematical framework that yields unique solutions and exact confidence intervals for regression coefficients. Building on Part I of this series, this article acquaints the reader with some of the important concepts in multiple regression analysis. These include multicollinearity, interaction effects, and an expansion of the discussion of inference testing, leverage, and variable transformations to multivariate models. Examples from the first article in this series are expanded on using a primarily graphic, rather than mathematical, approach. The importance of the relationships among the predictor variables and the dependence of the multivariate model coefficients on the choice of these variables are stressed. Finally, concepts in regression model building are discussed.

Boosted beta regression.

Directory of Open Access Journals (Sweden)

Matthias Schmid

Full Text Available Regression analysis with a bounded outcome is a common problem in applied statistics. Typical examples include regression models for percentage outcomes and the analysis of ratings that are measured on a bounded scale. In this paper, we consider beta regression, which is a generalization of logit models to situations where the response is continuous on the interval (0,1. Consequently, beta regression is a convenient tool for analyzing percentage responses. The classical approach to fit a beta regression model is to use maximum likelihood estimation with subsequent AIC-based variable selection. As an alternative to this established - yet unstable - approach, we propose a new estimation technique called boosted beta regression. With boosted beta regression estimation and variable selection can be carried out simultaneously in a highly efficient way. Additionally, both the mean and the variance of a percentage response can be modeled using flexible nonlinear covariate effects. As a consequence, the new method accounts for common problems such as overdispersion and non-binomial variance structures.

Regression to Causality : Regression-style presentation influences causal attribution

DEFF Research Database (Denmark)

Bordacconi, Mats Joe; Larsen, Martin Vinæs

2014-01-01

of equivalent results presented as either regression models or as a test of two sample means. Our experiment shows that the subjects who were presented with results as estimates from a regression model were more inclined to interpret these results causally. Our experiment implies that scholars using regression...... models – one of the primary vehicles for analyzing statistical results in political science – encourage causal interpretation. Specifically, we demonstrate that presenting observational results in a regression model, rather than as a simple comparison of means, makes causal interpretation of the results...... more likely. Our experiment drew on a sample of 235 university students from three different social science degree programs (political science, sociology and economics), all of whom had received substantial training in statistics. The subjects were asked to compare and evaluate the validity...

A Brief Talk on American Cultural Values: Reflected on the Movie the Pursuit of Happiness

Directory of Open Access Journals (Sweden)

Temmy Temmy

2009-05-01

Full Text Available America as one of world’s biggest developed countries has a very strong influence on global economy, politics, education, science, and military. America is also one of teaching Chinese as a foreign language destinations, therefore understanding American cultural values is very important. Article represents American cultural values based on a true story movie "The pursuit of Happiness". Research method applied was library research. It can be concluded that the characters, setting, and conflicts really presented the characteristics of American society.  

Optimizing engagement in goal pursuit with youth with physical disabilities attending life skills and transition programs: an exploratory study.

Science.gov (United States)

Smart, Eric; Aulakh, Adeeta; McDougall, Carolyn; Rigby, Patty; King, Gillian

2017-10-01

Identify strategies youth perceive will optimize their engagement in goal pursuit in life skills and transition programs using an engagement framework involving affective, cognitive, and behavioral components. A qualitative descriptive design was used. Two semi-structured interviews were conducted with seven youth. The first was informed by a prior observation session, and the second occurred after the program ended and explored youths' perceptions of whether and how their engagement changed. Data were analyzed using thematic analysis. The analysis generated eight strategies youth considered effective. These were categorized under the three components of engagement. Affective strategies: (1) building a relationship on familiarity and reciprocity; and (2) guiding the program using youths' preferences and strengths. Cognitive strategies: (3) assisting youth to envision meaningful change; (4) utilizing youths' learning styles; and (5) promoting awareness of goal progress. Behavioral strategies: (6) ensuring youth access to a resource network; (7) providing youth multiple decision opportunities; and (8) enabling youth to showcase capabilities. Service providers together with youth are encouraged to consider the role of context and self-determination needs in order to optimize youth engagement in goal pursuit. Systematic approaches to studying engagement are necessary to learn how to maximize rehabilitation potential. Implications for Rehabilitation Service providers are encouraged to be aware of the nature of engagement strategies identified by youth. Comprehensive frameworks of engagement are essential to generate knowledge on the range of strategies service providers can use to engage clients in rehabilitation services. Strategies perceived by youth to optimize their engagement in goal pursuit in life skills and transition programs have subtle yet significant differences with strategies used in other rehabilitation settings like mental health and adult healthcare

Action and pursuit of the summit of the earth

International Nuclear Information System (INIS)

Saavedra, Sandra; Guerrero, Juan Carlos

1996-01-01

The effect to guarantee the execution and of the commitments and activities to materialize the agreements and the program 21 emanated of the summit of the earth, the international community gathered in Rio called in that program to conform a Commission of Sustainable Development (CSD) through the United Nations (UN) In its session number forty seven of 1992, the general assembly of the UN defined, by means of the resolution 471 191, the composition of the CSD, the bases for the participation of the non government organizations (ONG) in her and its relationship with other organisms of the UN. Today the commission has an own secretary and it is attributed to the Economic and Social Council (ECOSOC) The CSD should carry out an effective pursuit on the world execution of all the commitments acquired in the conference of Rio, evaluating, mainly, the progressive application of the program 21 to national, regional and international scale. It also promotes the development of the international cooperation and it contributes to rationalize the process of taking of intergovernmental decisions as regards sustainable development

In Pursuit of an Alternative Academy: The Case of Kocaeli Academy for Solidarity (Non-Peer-Reviewed Reflection Article

Directory of Open Access Journals (Sweden)

Güven Bakırezer

2018-01-01

Full Text Available After declaring a state of emergency on 20 July, 2016 as a response to the failed coup attempt of 15 July, 2016, the Turkish government launched a nation-wide academic purge, especially targeting the Academics for Peace. This group of academics signed a peace petition in January 2016 to address civilian deaths in the South-Eastern part of the country and to urge the government to take responsibility and restart the peace process. Having the largest number of peace petitioners among Turkey’s provincial universities, Kocaeli University was the first to dismiss all 19 of the peace academics from their positions on 1 September, 2016. Already active in defending the universal values of academia in other venues, these dismissed peace academics founded the Kocaeli Academy of Solidarity in pursuit of an alternative academy that aims to bring together university students, NGO members and ordinary citizens in the city in a cooperative understanding of education and research. After weekly seminars over eight months, a summer school of five days, and with applications in for funding its projects, particularly amongst others the School of Life, Kocaeli Academy for Solidarity has a strong determination to demonstrate a new democratic model of education and research.

Illusory object motion in the centre of a radial pattern: The Pursuit-Pursuing illusion.

Science.gov (United States)

Ito, Hiroyuki

2012-01-01

A circular object placed in the centre of a radial pattern consisting of thin sectors was found to cause a robust motion illusion. During eye-movement pursuit of a moving target, the presently described stimulus produced illusory background-object motion in the same direction as that of the eye movement. In addition, the display induced illusory stationary perception of a moving object against the whole display motion. In seven experiments, the characteristics of the illusion were examined in terms of luminance relationships and figural characteristics of the radial pattern. Some potential explanations for these findings are discussed.

Illness perception and quality of life of HIV-positive persons: mediation effects of tenacious and flexible goal pursuit.

Science.gov (United States)

Catunda, Carolina; Seidl, Eliane Maria Fleury; Lemétayer, Fabienne

2017-02-01

Medical advances contribute to raise life expectancy of people living with HIV/AIDS (PLHIV). However, they still face challenges related to the disease, thus, quality of life (QOL) became a priority on the field. The self-regulatory model (SRM) guided this study. Illness perceptions (IP) are the beliefs, cognitions, representations of a disease, impacting PLHIV coping strategies and QOL. Tenacious goal pursuit (TGP) is the pursuit of goals with determination, flexible goal adjustment (FGA) is doing it with flexibility, disengaging if necessary, they can both be considered as coping strategies. This study aims to measure the impact of HIV Perception in the QOL of PLHIV mediated by the TGP and FGA. Data was collected from 196 PLHIV with the WHOQOL-HIV Bref, the Brief-IPQ and the FGA and TGP scales. Structural equation model provided a good fit consistent with the theoretical SRM. IP, TGP and FGA had direct effects on the QOL of PLHIV. IP had also an indirect effect (partially mediated by TGP/FGA), suggesting that TGP/FGA reduce the impact of a threatening IP in the QOL. Goal oriented interventions should focus in the HIV perception of PLHIV to ameliorate their QOL.

Does Context, Practice or Competition Affect Female Athletes’ Achievement Goal Dominance, Goal Pursuit, Burnout and Motivation?

Directory of Open Access Journals (Sweden)

Fernández-Rio Javier

2017-10-01

Full Text Available The goal of this study was to assess the effects of two different achievement sport contexts, practice and competition, on the motivational profile of professional/semi-professional athletes. Forty-eight Spanish national/international-level female athletes (basketball = 18; handball = 12; soccer = 11; volleyball = 7, mean age 25.14 ± 3.43 years, agreed to participate in the study. They completed a questionnaire, prior and after training and competition, to assess achievement goals, achievement goal dominance, goal pursuit, motivational climate, motivation, burnout and perceived recovery-exertion. Data analyses revealed that, both in practice and competition, these team-sport athletes overwhelmingly showed a strong mastery-approach achievement goal in dominance as well as in pursuit. A significant finding was that this group of national/international-level, professional/semi-professional athletes not only adopted a mastery-approach achievement goal, but they also actively pursued it. It is also remarkable that this profile remained stable at post-tests, even after a painful defeat in competition, which produced a significant negative effect on the athletes’ burnout (emotional and physical exhaustion and devaluation of sport participation and self-determined motivation. As expected, the difference between total recovery and perceived exertion significantly increased after practice and competition. National/international-level team-sport professional/semi-professional female athletes held and pursue stable mastery-approach goal dominance.

Brasiguaio Identities: An outcome of the pursuit of land across the Brazilian and Paraguayan shared border region

Directory of Open Access Journals (Sweden)

Marcos Estrada

2017-10-01

Full Text Available The movement of people between places is far from being a new or isolated phenomenon and is happening more often than before. This is also the case for individuals who moved from Brazil and Paraguay. Based on the existing literature as well as on data gathered in the landless camp Antônio Irmão, also known locally as the ‘Brasiguaios landless camp’ in Itaquiraí in the state of Mato Grosso do Sul, Brazil, this article explains how their search for a piece of land in either Brazil and Paraguay influenced the formation of the Brasiguaios identities. First, I briefly approach the foundation of transnationalism scholarship, which guided my research. Next, I demonstrate how land policies in Brazil and Paraguay, aimed at developing their respective border regions, played a role in the migration of Brazilians to Paraguayan and then the return of a number of them to Brazil. Last, I share the narrative of individuals in the Brasiguaio landless camp in the pursuit of land in either country. At the core of my argument is that the Brasiguaio identities of this landless group result from their pursuit of land rather than from migration processes.

Nested Multi- and Many-Objective Optimisation of Team Track Pursuit Cycling

Directory of Open Access Journals (Sweden)

Markus Wagner

2016-10-01

Full Text Available Team pursuit track cycling is an elite sport that is part of the Summer Olympics. Teams race against each other on special tracks called velodromes. In this article, we create racing strategies that allow the team to complete the race in as little time as possible. In addition to the traditional minimisation of the race times, we consider the amount of energy that the riders have left at the end of the race. For the team coach this extension can have the benefit that a diverse set of trade-off strategies can be considered. For the optimisation approach, the added diversity can help to get over local optima.To solve this problem, we apply different state-of-the-art algorithms with problem-specific variation operators. It turns out that nesting algorithms is beneficial for achieving fast strategies reliably.

The effect of visual-motion time delays on pilot performance in a pursuit tracking task

Science.gov (United States)

Miller, G. K., Jr.; Riley, D. R.

1976-01-01

A study has been made to determine the effect of visual-motion time delays on pilot performance of a simulated pursuit tracking task. Three interrelated major effects have been identified: task difficulty, motion cues, and time delays. As task difficulty, as determined by airplane handling qualities or target frequency, increases, the amount of acceptable time delay decreases. However, when relatively complete motion cues are included in the simulation, the pilot can maintain his performance for considerably longer time delays. In addition, the number of degrees of freedom of motion employed is a significant factor.

On generalized elliptical quantiles in the nonlinear quantile regression setup

Czech Academy of Sciences Publication Activity Database

Hlubinka, D.; Šiman, Miroslav

2015-01-01

Roč. 24, č. 2 (2015), s. 249-264 ISSN 1133-0686 R&D Projects: GA ČR GA14-07234S Institutional support: RVO:67985556 Keywords : multivariate quantile * elliptical quantile * quantile regression * multivariate statistical inference * portfolio optimization Subject RIV: BA - General Mathematics Impact factor: 1.207, year: 2015 http://library.utia.cas.cz/separaty/2014/SI/siman-0434510.pdf

Modeling oil production based on symbolic regression

International Nuclear Information System (INIS)

Yang, Guangfei; Li, Xianneng; Wang, Jianliang; Lian, Lian; Ma, Tieju

2015-01-01

Numerous models have been proposed to forecast the future trends of oil production and almost all of them are based on some predefined assumptions with various uncertainties. In this study, we propose a novel data-driven approach that uses symbolic regression to model oil production. We validate our approach on both synthetic and real data, and the results prove that symbolic regression could effectively identify the true models beneath the oil production data and also make reliable predictions. Symbolic regression indicates that world oil production will peak in 2021, which broadly agrees with other techniques used by researchers. Our results also show that the rate of decline after the peak is almost half the rate of increase before the peak, and it takes nearly 12 years to drop 4% from the peak. These predictions are more optimistic than those in several other reports, and the smoother decline will provide the world, especially the developing countries, with more time to orchestrate mitigation plans. -- Highlights: •A data-driven approach has been shown to be effective at modeling the oil production. •The Hubbert model could be discovered automatically from data. •The peak of world oil production is predicted to appear in 2021. •The decline rate after peak is half of the increase rate before peak. •Oil production projected to decline 4% post-peak

The Controversy Behind the Air Corps Tactical School's Strategic Bombardment Theory: An Analysis of the Bombardment Versus Pursuit Aviation Data Between 1930-1939

National Research Council Canada - National Science Library

Severs, Hugh

1997-01-01

... at the expense of pursuit aviation. The report used primary source data from the Air Force Historical Research Agency and various secondary sources to analyze results of Air Corps training exercises and combat data from overseas conflicts...

Regression analysis with categorized regression calibrated exposure: some interesting findings

Directory of Open Access Journals (Sweden)

Hjartåker Anette

2006-07-01

Full Text Available Abstract Background Regression calibration as a method for handling measurement error is becoming increasingly well-known and used in epidemiologic research. However, the standard version of the method is not appropriate for exposure analyzed on a categorical (e.g. quintile scale, an approach commonly used in epidemiologic studies. A tempting solution could then be to use the predicted continuous exposure obtained through the regression calibration method and treat it as an approximation to the true exposure, that is, include the categorized calibrated exposure in the main regression analysis. Methods We use semi-analytical calculations and simulations to evaluate the performance of the proposed approach compared to the naive approach of not correcting for measurement error, in situations where analyses are performed on quintile scale and when incorporating the original scale into the categorical variables, respectively. We also present analyses of real data, containing measures of folate intake and depression, from the Norwegian Women and Cancer study (NOWAC. Results In cases where extra information is available through replicated measurements and not validation data, regression calibration does not maintain important qualities of the true exposure distribution, thus estimates of variance and percentiles can be severely biased. We show that the outlined approach maintains much, in some cases all, of the misclassification found in the observed exposure. For that reason, regression analysis with the corrected variable included on a categorical scale is still biased. In some cases the corrected estimates are analytically equal to those obtained by the naive approach. Regression calibration is however vastly superior to the naive method when applying the medians of each category in the analysis. Conclusion Regression calibration in its most well-known form is not appropriate for measurement error correction when the exposure is analyzed on a

Projection-based curve clustering

International Nuclear Information System (INIS)

Auder, Benjamin; Fischer, Aurelie

2012-01-01

This paper focuses on unsupervised curve classification in the context of nuclear industry. At the Commissariat a l'Energie Atomique (CEA), Cadarache (France), the thermal-hydraulic computer code CATHARE is used to study the reliability of reactor vessels. The code inputs are physical parameters and the outputs are time evolution curves of a few other physical quantities. As the CATHARE code is quite complex and CPU time-consuming, it has to be approximated by a regression model. This regression process involves a clustering step. In the present paper, the CATHARE output curves are clustered using a k-means scheme, with a projection onto a lower dimensional space. We study the properties of the empirically optimal cluster centres found by the clustering method based on projections, compared with the 'true' ones. The choice of the projection basis is discussed, and an algorithm is implemented to select the best projection basis among a library of orthonormal bases. The approach is illustrated on a simulated example and then applied to the industrial problem. (authors)

Consensus pursuit of heterogeneous multi-agent systems under a directed acyclic graph

Science.gov (United States)

Yan, Jing; Guan, Xin-Ping; Luo, Xiao-Yuan

2011-04-01

This paper is concerned with the cooperative target pursuit problem by multiple agents based on directed acyclic graph. The target appears at a random location and moves only when sensed by the agents, and agents will pursue the target once they detect its existence. Since the ability of each agent may be different, we consider the heterogeneous multi-agent systems. According to the topology of the multi-agent systems, a novel consensus-based control law is proposed, where the target and agents are modeled as a leader and followers, respectively. Based on Mason's rule and signal flow graph analysis, the convergence conditions are provided to show that the agents can catch the target in a finite time. Finally, simulation studies are provided to verify the effectiveness of the proposed approach.

Recruiting highly educated graduates: a study on the relationship between recruitment information sources, the theory of planned behavior, and actual job pursuit

NARCIS (Netherlands)

Jaidi, Y.; van Hooft, E.A.J.; Arends, L.R.

2011-01-01

Using the theory of planned behavior, we examined the effects of different recruitment-related information sources on the job pursuit of highly educated graduates. The study was conducted using a real-life longitudinal design. Participants reported on potential employers they were interested in. We

A method for evaluating the funding of components of natural resource and conservation projects

Energy Technology Data Exchange (ETDEWEB)

Wellington, John F., E-mail: welling@ipfw.edu [Indiana University – Purdue University Fort Wayne (IPFW), Doermer School of Business, 203 Stonegate Drive Erie, PA 16505 (United States); Lewis, Stephen A., E-mail: lewis.sa07@gmail.com [Mongrel Works, LLC., Columbus, OH 43209 (United States)

2016-02-15

Many public and private entities such as government agencies and private foundations have missions related to the improvement, protection, and sustainability of the environment. In pursuit of their missions, they fund projects with related outcomes. Typically, the funding scene consists of scarce funding dollars for the many project requests. In light of funding limitations and funder's search for innovative funding schemes, a method to support the allocation of scarce dollars among project components is presented. The proposed scheme has similarities to methods in the project selection literature but differs in its focus on project components and its connection to and enumeration of the universe of funding possibilities. The value of having access to the universe is demonstrated with illustrations. The presentation includes Excel implementations that should appeal to a broad spectrum of project evaluators and reviewers. Access to the space of funding possibilities facilitates a rich analysis of funding alternatives. - Highlights: • Method is given for allocating scarce funding dollars among competing projects. • Allocations are made to fund parts of projects • Proposed method provides access to the universe of funding possibilities. • Proposed method facilitates a rich analysis of funding possibilities. • Excel spreadsheet implementations are provided.

Effects of Goal Relations on Self-Regulated Learning in Multiple Goal Pursuits: Performance, the Self-Regulatory Process, and Task Enjoyment

Science.gov (United States)

Lee, Hyunjoo

2012-01-01

The purpose of this study was to investigate the effects of goal relations on self-regulation in the pursuit of multiple goals, focusing on self-regulated performance, the self-regulatory process, and task enjoyment. The effect of multiple goal relations on self-regulation was explored in a set of three studies. Goal relations were divided into…

Time-adaptive quantile regression

DEFF Research Database (Denmark)

Møller, Jan Kloppenborg; Nielsen, Henrik Aalborg; Madsen, Henrik

2008-01-01

and an updating procedure are combined into a new algorithm for time-adaptive quantile regression, which generates new solutions on the basis of the old solution, leading to savings in computation time. The suggested algorithm is tested against a static quantile regression model on a data set with wind power......An algorithm for time-adaptive quantile regression is presented. The algorithm is based on the simplex algorithm, and the linear optimization formulation of the quantile regression problem is given. The observations have been split to allow a direct use of the simplex algorithm. The simplex method...... production, where the models combine splines and quantile regression. The comparison indicates superior performance for the time-adaptive quantile regression in all the performance parameters considered....

Similar effects of feature-based attention on motion perception and pursuit eye movements at different levels of awareness

OpenAIRE

Spering, Miriam; Carrasco, Marisa

2012-01-01

Feature-based attention enhances visual processing and improves perception, even for visual features that we are not aware of. Does feature-based attention also modulate motor behavior in response to visual information that does or does not reach awareness? Here we compare the effect of feature-based attention on motion perception and smooth pursuit eye movements in response to moving dichoptic plaids–stimuli composed of two orthogonally-drifting gratings, presented separately to each eye–in ...

Regression Models and Fuzzy Logic Prediction of TBM Penetration Rate

Directory of Open Access Journals (Sweden)

Minh Vu Trieu

2017-03-01

Full Text Available This paper presents statistical analyses of rock engineering properties and the measured penetration rate of tunnel boring machine (TBM based on the data of an actual project. The aim of this study is to analyze the influence of rock engineering properties including uniaxial compressive strength (UCS, Brazilian tensile strength (BTS, rock brittleness index (BI, the distance between planes of weakness (DPW, and the alpha angle (Alpha between the tunnel axis and the planes of weakness on the TBM rate of penetration (ROP. Four (4 statistical regression models (two linear and two nonlinear are built to predict the ROP of TBM. Finally a fuzzy logic model is developed as an alternative method and compared to the four statistical regression models. Results show that the fuzzy logic model provides better estimations and can be applied to predict the TBM performance. The R-squared value (R2 of the fuzzy logic model scores the highest value of 0.714 over the second runner-up of 0.667 from the multiple variables nonlinear regression model.

Regression Models and Fuzzy Logic Prediction of TBM Penetration Rate

Science.gov (United States)

Minh, Vu Trieu; Katushin, Dmitri; Antonov, Maksim; Veinthal, Renno

2017-03-01

This paper presents statistical analyses of rock engineering properties and the measured penetration rate of tunnel boring machine (TBM) based on the data of an actual project. The aim of this study is to analyze the influence of rock engineering properties including uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), rock brittleness index (BI), the distance between planes of weakness (DPW), and the alpha angle (Alpha) between the tunnel axis and the planes of weakness on the TBM rate of penetration (ROP). Four (4) statistical regression models (two linear and two nonlinear) are built to predict the ROP of TBM. Finally a fuzzy logic model is developed as an alternative method and compared to the four statistical regression models. Results show that the fuzzy logic model provides better estimations and can be applied to predict the TBM performance. The R-squared value (R2) of the fuzzy logic model scores the highest value of 0.714 over the second runner-up of 0.667 from the multiple variables nonlinear regression model.

Assessing the performance of variational methods for mixed logistic regression models

Czech Academy of Sciences Publication Activity Database

Rijmen, F.; Vomlel, Jiří

2008-01-01

Roč. 78, č. 8 (2008), s. 765-779 ISSN 0094-9655 R&D Projects: GA MŠk 1M0572 Grant - others:GA MŠk(CZ) 2C06019 Institutional research plan: CEZ:AV0Z10750506 Keywords : Mixed models * Logistic regression * Variational methods * Lower bound approximation Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.353, year: 2008

Consumer engagement: An insight from smart grid projects in Europe

International Nuclear Information System (INIS)

Gangale, Flavia; Mengolini, Anna; Onyeji, Ijeoma

2013-01-01

This paper provides an insight into consumer engagement in smart grid projects in Europe. Projects analysed are those included in the catalogue annexed in the JRC Report “Smart Grid projects in Europe: lessons learned and current developments”. The analysis suggests an increase in the interest in consumer engagement projects at European level and a strong focus on the residential sector, and emphasises the key importance of public funding to support these projects. The study also reveals that projects involving consumers are characterised by the pursuit of two main objectives: gaining deeper knowledge of consumer behaviour (observing and understanding the consumer) and motivating and empowering consumers to become active energy customers (engaging the consumer). The paper reviews the main activities undertaken to obtain these objectives and highlights trends and developments in the field. Finally, the paper discusses obstacles to consumer engagement and the strategies adopted by the projects surveyed to tackle them, highlighting the need to build consumer trust and to design targeted campaigns taking into consideration different consumer segments. The conclusions are in line with findings and analyses presented in the literature and underscore the need for further research and action at European level. - Highlights: • Consumers' key role in the success of the future electricity system (smart grids). • Survey on consumer engagement experiences in European smart grid projects. • Focus is on observing and understanding the consumers and on engaging them. • Trust and confidence as central elements. • Need to take into consideration different consumer segments/motivational factors

The pursuit of happiness measurement: a psychometric model based on psychophysiological correlates.

Science.gov (United States)

Pietro, Cipresso; Silvia, Serino; Giuseppe, Riva

2014-01-01

Everyone is interested in the pursuit of happiness, but the real problem for the researchers is how to measure it. Our aim was to deeply investigate happiness measurement through biomedical signals, using psychophysiological methods to objectify the happiness experiences measurements. The classic valence-arousal model of affective states to study happiness has been extensively used in psychophysiology. However, really few studies considered a real combination of these two dimensions and no study further investigated multidimensional models. More, most studies focused mainly on self-report to measure happiness and a deeper psychophysiological investigation on the dimensions of such an experience is still missing. A multidimensional model of happiness is presented and both the dimensions and the measures extracted within each dimension are comprehensively explained. This multidimensional model aims at being a milestone for future systematic study on psychophysiology of happiness and affective states.

Sensor-based vibration signal feature extraction using an improved composite dictionary matching pursuit algorithm.

Science.gov (United States)

Cui, Lingli; Wu, Na; Wang, Wenjing; Kang, Chenhui

2014-09-09

This paper presents a new method for a composite dictionary matching pursuit algorithm, which is applied to vibration sensor signal feature extraction and fault diagnosis of a gearbox. Three advantages are highlighted in the new method. First, the composite dictionary in the algorithm has been changed from multi-atom matching to single-atom matching. Compared to non-composite dictionary single-atom matching, the original composite dictionary multi-atom matching pursuit (CD-MaMP) algorithm can achieve noise reduction in the reconstruction stage, but it cannot dramatically reduce the computational cost and improve the efficiency in the decomposition stage. Therefore, the optimized composite dictionary single-atom matching algorithm (CD-SaMP) is proposed. Second, the termination condition of iteration based on the attenuation coefficient is put forward to improve the sparsity and efficiency of the algorithm, which adjusts the parameters of the termination condition constantly in the process of decomposition to avoid noise. Third, composite dictionaries are enriched with the modulation dictionary, which is one of the important structural characteristics of gear fault signals. Meanwhile, the termination condition of iteration settings, sub-feature dictionary selections and operation efficiency between CD-MaMP and CD-SaMP are discussed, aiming at gear simulation vibration signals with noise. The simulation sensor-based vibration signal results show that the termination condition of iteration based on the attenuation coefficient enhances decomposition sparsity greatly and achieves a good effect of noise reduction. Furthermore, the modulation dictionary achieves a better matching effect compared to the Fourier dictionary, and CD-SaMP has a great advantage of sparsity and efficiency compared with the CD-MaMP. The sensor-based vibration signals measured from practical engineering gearbox analyses have further shown that the CD-SaMP decomposition and reconstruction algorithm

METHODOLOGY AND RESULTS OF MOBILE OBJECT PURSUIT PROBLEM SOLUTION WITH TWO-STAGE DYNAMIC SYSTEM

Directory of Open Access Journals (Sweden)

A. Kiselev Mikhail

2017-01-01

Full Text Available The experience of developing unmanned fighting vehicles indicates that the main challenge in this field reduces itself to creating the systems which can replace the pilot both as a sensor and as the operator of the flight. This problem can be partial- ly solved by introducing remote control, but there are certain flight segments where it can only be executed under fully inde- pendent control and data support due to various reasons, such as tight time, short duration, lack of robust communication, etc. Such stages also include close-range air combat maneuvering (CRACM - a key flight segment as far as the fighter's purpose is concerned, which also places the highest demands on the fighter's design. Until recently the creation of an unmanned fighter airplane has been a fundamentally impossible task due to the absence of sensors able to provide the necessary data support to control the fighter during CRACM. However, the development prospects of aircraft hardware (passive type flush antennae, op- tico-locating panoramic view stations are indicative of producing possible solutions to this problem in the nearest future. There- fore, presently the only fundamental impediment on the way to developing an unmanned fighting aircraft is the problem of cre- ating algorithms for automatic trajectory control during CRACM. This paper presents the strategy of automatic trajectory con- trol synthesis by a two-stage dynamic system aiming to reach the conditions specified with respect to an object in pursuit. It contains certain results of control algorithm parameters impact assessment in regards to the pursuit mission effectiveness. Based on the obtained results a deduction is drawn pertaining to the efficiency of the offered method and its possible utilization in au- tomated control of an unmanned fighting aerial vehicle as well as organizing group interaction during CRACM.

Sensor-Based Vibration Signal Feature Extraction Using an Improved Composite Dictionary Matching Pursuit Algorithm

Directory of Open Access Journals (Sweden)

Lingli Cui

2014-09-01

Full Text Available This paper presents a new method for a composite dictionary matching pursuit algorithm, which is applied to vibration sensor signal feature extraction and fault diagnosis of a gearbox. Three advantages are highlighted in the new method. First, the composite dictionary in the algorithm has been changed from multi-atom matching to single-atom matching. Compared to non-composite dictionary single-atom matching, the original composite dictionary multi-atom matching pursuit (CD-MaMP algorithm can achieve noise reduction in the reconstruction stage, but it cannot dramatically reduce the computational cost and improve the efficiency in the decomposition stage. Therefore, the optimized composite dictionary single-atom matching algorithm (CD-SaMP is proposed. Second, the termination condition of iteration based on the attenuation coefficient is put forward to improve the sparsity and efficiency of the algorithm, which adjusts the parameters of the termination condition constantly in the process of decomposition to avoid noise. Third, composite dictionaries are enriched with the modulation dictionary, which is one of the important structural characteristics of gear fault signals. Meanwhile, the termination condition of iteration settings, sub-feature dictionary selections and operation efficiency between CD-MaMP and CD-SaMP are discussed, aiming at gear simulation vibration signals with noise. The simulation sensor-based vibration signal results show that the termination condition of iteration based on the attenuation coefficient enhances decomposition sparsity greatly and achieves a good effect of noise reduction. Furthermore, the modulation dictionary achieves a better matching effect compared to the Fourier dictionary, and CD-SaMP has a great advantage of sparsity and efficiency compared with the CD-MaMP. The sensor-based vibration signals measured from practical engineering gearbox analyses have further shown that the CD-SaMP decomposition and

Regression analysis by example

CERN Document Server

Chatterjee, Samprit

2012-01-01

Praise for the Fourth Edition: ""This book is . . . an excellent source of examples for regression analysis. It has been and still is readily readable and understandable."" -Journal of the American Statistical Association Regression analysis is a conceptually simple method for investigating relationships among variables. Carrying out a successful application of regression analysis, however, requires a balance of theoretical results, empirical rules, and subjective judgment. Regression Analysis by Example, Fifth Edition has been expanded

Applied logistic regression

CERN Document Server

Hosmer, David W; Sturdivant, Rodney X

2013-01-01

 A new edition of the definitive guide to logistic regression modeling for health science and other applications This thoroughly expanded Third Edition provides an easily accessible introduction to the logistic regression (LR) model and highlights the power of this model by examining the relationship between a dichotomous outcome and a set of covariables. Applied Logistic Regression, Third Edition emphasizes applications in the health sciences and handpicks topics that best suit the use of modern statistical software. The book provides readers with state-of-

Normalization Ridge Regression in Practice I: Comparisons Between Ordinary Least Squares, Ridge Regression and Normalization Ridge Regression.

Science.gov (United States)

Bulcock, J. W.

The problem of model estimation when the data are collinear was examined. Though the ridge regression (RR) outperforms ordinary least squares (OLS) regression in the presence of acute multicollinearity, it is not a problem free technique for reducing the variance of the estimates. It is a stochastic procedure when it should be nonstochastic and it…

Vector regression introduced

Directory of Open Access Journals (Sweden)

Mok Tik

2014-06-01

Full Text Available This study formulates regression of vector data that will enable statistical analysis of various geodetic phenomena such as, polar motion, ocean currents, typhoon/hurricane tracking, crustal deformations, and precursory earthquake signals. The observed vector variable of an event (dependent vector variable is expressed as a function of a number of hypothesized phenomena realized also as vector variables (independent vector variables and/or scalar variables that are likely to impact the dependent vector variable. The proposed representation has the unique property of solving the coefficients of independent vector variables (explanatory variables also as vectors, hence it supersedes multivariate multiple regression models, in which the unknown coefficients are scalar quantities. For the solution, complex numbers are used to rep- resent vector information, and the method of least squares is deployed to estimate the vector model parameters after transforming the complex vector regression model into a real vector regression model through isomorphism. Various operational statistics for testing the predictive significance of the estimated vector parameter coefficients are also derived. A simple numerical example demonstrates the use of the proposed vector regression analysis in modeling typhoon paths.

Applied linear regression

CERN Document Server

Weisberg, Sanford

2013-01-01

Praise for the Third Edition ""...this is an excellent book which could easily be used as a course text...""-International Statistical Institute The Fourth Edition of Applied Linear Regression provides a thorough update of the basic theory and methodology of linear regression modeling. Demonstrating the practical applications of linear regression analysis techniques, the Fourth Edition uses interesting, real-world exercises and examples. Stressing central concepts such as model building, understanding parameters, assessing fit and reliability, and drawing conclusions, the new edition illus

The enduring value of Gánti's chemoton model and life criteria: Heuristic pursuit of exact theoretical biology.

Science.gov (United States)

Griesemer, James

2015-09-21

Gánti's chemoton model of the minimal chemical organization of living systems and life criteria for the living state and a living world are characterized. It is argued that these are better interpreted as part of a heuristic pursuit of an exact theoretical biology than as a "definition of life." Several problems with efforts to define life are discussed. Clarifying the proper use of Gánti's ideas to serve constructive engineering idealizations helps to show their enduring value. Copyright © 2015 Elsevier Ltd. All rights reserved.

Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy.

Science.gov (United States)

Shakespeare, Timothy J; Kaski, Diego; Yong, Keir X X; Paterson, Ross W; Slattery, Catherine F; Ryan, Natalie S; Schott, Jonathan M; Crutch, Sebastian J

2015-07-01

The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal 'visual dementia' and most common atypical Alzheimer's disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients' (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer's disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer's disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer's disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with 'sticky fixation'. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer's disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large saccadic intrusions

Understanding poisson regression.

Science.gov (United States)

Hayat, Matthew J; Higgins, Melinda

2014-04-01

Nurse investigators often collect study data in the form of counts. Traditional methods of data analysis have historically approached analysis of count data either as if the count data were continuous and normally distributed or with dichotomization of the counts into the categories of occurred or did not occur. These outdated methods for analyzing count data have been replaced with more appropriate statistical methods that make use of the Poisson probability distribution, which is useful for analyzing count data. The purpose of this article is to provide an overview of the Poisson distribution and its use in Poisson regression. Assumption violations for the standard Poisson regression model are addressed with alternative approaches, including addition of an overdispersion parameter or negative binomial regression. An illustrative example is presented with an application from the ENSPIRE study, and regression modeling of comorbidity data is included for illustrative purposes. Copyright 2014, SLACK Incorporated.

Alternative Methods of Regression

CERN Document Server

Birkes, David

2011-01-01

Of related interest. Nonlinear Regression Analysis and its Applications Douglas M. Bates and Donald G. Watts ".an extraordinary presentation of concepts and methods concerning the use and analysis of nonlinear regression models.highly recommend[ed].for anyone needing to use and/or understand issues concerning the analysis of nonlinear regression models." --Technometrics This book provides a balance between theory and practice supported by extensive displays of instructive geometrical constructs. Numerous in-depth case studies illustrate the use of nonlinear regression analysis--with all data s

OPLS statistical model versus linear regression to assess sonographic predictors of stroke prognosis.

Science.gov (United States)

Vajargah, Kianoush Fathi; Sadeghi-Bazargani, Homayoun; Mehdizadeh-Esfanjani, Robab; Savadi-Oskouei, Daryoush; Farhoudi, Mehdi

2012-01-01

The objective of the present study was to assess the comparable applicability of orthogonal projections to latent structures (OPLS) statistical model vs traditional linear regression in order to investigate the role of trans cranial doppler (TCD) sonography in predicting ischemic stroke prognosis. The study was conducted on 116 ischemic stroke patients admitted to a specialty neurology ward. The Unified Neurological Stroke Scale was used once for clinical evaluation on the first week of admission and again six months later. All data was primarily analyzed using simple linear regression and later considered for multivariate analysis using PLS/OPLS models through the SIMCA P+12 statistical software package. The linear regression analysis results used for the identification of TCD predictors of stroke prognosis were confirmed through the OPLS modeling technique. Moreover, in comparison to linear regression, the OPLS model appeared to have higher sensitivity in detecting the predictors of ischemic stroke prognosis and detected several more predictors. Applying the OPLS model made it possible to use both single TCD measures/indicators and arbitrarily dichotomized measures of TCD single vessel involvement as well as the overall TCD result. In conclusion, the authors recommend PLS/OPLS methods as complementary rather than alternative to the available classical regression models such as linear regression.

Pure-Pursuit Reactive Path Tracking for Nonholonomic Mobile Robots with a 2D Laser Scanner

Directory of Open Access Journals (Sweden)

Jesús Morales

2009-01-01

Full Text Available Due to its simplicity and efficiency, the pure-pursuit path tracking method has been widely employed for planned navigation of nonholonomic ground vehicles. In this paper, we investigate the application of this technique for reactive tracking of paths that are implicitly defined by perceived environmental features. Goal points are obtained through an efficient interpretation of range data from an onboard 2D laser scanner to follow persons, corridors, and walls. Moreover, this formulation allows that a robotic mission can be composed of a combination of different types of path segments. These techniques have been successfully tested in the tracked mobile robot Auriga-α in an indoor environment.

Corporate entrepreneurship orientation and the pursuit of innovating opportunities in Botswana

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Melodi Botha

2011-12-01

Full Text Available Purpose and objectives: A causal relationship between the independent variable (introduction of innovation and the dependent variable (Corporate Entrepreneurship orientation is explored by addressing the question: Do companies in Botswana have a corporate entrepreneurship (CE orientation that leads them to pursue innovating opportunities? The primary objective is to investigate how CE orientation in companies in Botswana is linked to individual employees' pursuit of innovation within corporate boundaries. Secondary objectives are to identify the prerequisites and factors of CE orientation, individual employees' perceptions and the importance of innovation factors in established companies. Problem investigated: To determine whether existing firms in Botswana represent the concept of an entrepreneurial company within the sphere of corporate entrepreneurship by pursuing innovating opportunities. The intention is to identify the knowledge, attitudes and beliefs of individuals as potential corporate entrepreneurs, their ability to be innovative and how such innovation is brought to fruition. Design and methodology: To obtain quantifiable measures of the link between CE orientation and innovation, a quantitative approach is used: a formalised, cross-sectional research design. The sample consists of 100 individuals at supervisory levels and above in large corporate companies, from eight different provinces in Botswana. A research instrument is used and convenience sampling employed. Factor analysis is performed on the questionnaire to determine its validity and reliability. A Pearson correlation coefficient test is conducted on the three factors identified in factor analysis. The chi-square test and T-test (Mann-Whitney U test are used to illustrate the statistically significant differences between the different variables and factors. Findings and implications: This paper proves the inextricable link between CE orientation and the pursuit of innovation

Introduction to regression graphics

CERN Document Server

Cook, R Dennis

2009-01-01

Covers the use of dynamic and interactive computer graphics in linear regression analysis, focusing on analytical graphics. Features new techniques like plot rotation. The authors have composed their own regression code, using Xlisp-Stat language called R-code, which is a nearly complete system for linear regression analysis and can be utilized as the main computer program in a linear regression course. The accompanying disks, for both Macintosh and Windows computers, contain the R-code and Xlisp-Stat. An Instructor's Manual presenting detailed solutions to all the problems in the book is ava

Cooperative option of pursuit game with two pursuers and one evader. A strong stability of division variety

Directory of Open Access Journals (Sweden)

Viktor D. Shiryayev

2017-06-01

Full Text Available Introduction: The article deals with a simple differential game on the plane of pursuit with two consistently active players and one evader E; the game is considered in the form of the characteristic function. Materials and Methods: The geometric constructions and methods are used for solving the problem. The security zone of the escapee is bounded by the Apollonius circle, the pursuit team uses a strategy of parallel approach. Results: A method of finding the optimal players strategies and the optimal players’ trajectory is proposed. The way of forming the characteristic function is provided. All the variety of division is considered as a solution. However, the use of the results of cooperative theory of differential games is impossible without solving the problems associated with the specifics of differential equations of motion. Foremost, it is the problem of dynamic stability of optimality principles. The article introduces an auxiliary function of making the redistribution of winnings in time, keeping his total winnings throughout the game. The dynamic stability of the cooperative solution is determined with the help of this function. Strong dynamic stability of the entire set of solutions is shown. Discussion and Conclusions: The obtained results are consistent with similar research of other authors. Further research in this field can be used in the development of methods for “regularization” of optimality principles, for which the condition of dynamic stability is always fulfilled.

Followers of Confucianism or a New Generation? Learning Culture of Mainland Chinese: In Pursuit of Western-Based Business Education Away from Mainland China

Science.gov (United States)

Rajaram, Kumaran

2013-01-01

The mainland Chinese learning culture has evolved due to the rapid changes in the economic, political, cultural and demographic demands. The changing characteristics of the Chinese students' learning behavioral styles and preferences, as well as the challenges faced in pursuit of Western-based education, are discussed with suggested…

Energy distribution for Coefficients of Redundant Signal Representations of Music

DEFF Research Database (Denmark)

Endelt, Line Ørtoft; la Cour-Harbo, Anders

2005-01-01

different time-frequency dictionaries. We have applied these methods to music to examine their ability to express music signals in a sparse manner for a number of dictionaries and window lengths. The evaluation is based on the m-term approximation needed to represent 90 %, 95 %, 99 % and 99......In this paper we investigate how the energy is distributed in the coefficients vector of various redundant signal representations of music signals. The representations are found using Basis Pursuit, Matching Pursuit, Alternating Projections, Best Orthogonal Basis and Method of Frames, with five.......9 % of the energy in the coefficients, also the time consummation for finding the representations are considered. The distribution of energy in the coefficients of the representations found using Basis Pursuit, Matching Pursuit, Alternating Projections and Best Orthogonal Basis depends mainly on the signal...

The effect of visual-motion time-delays on pilot performance in a simulated pursuit tracking task

Science.gov (United States)

Miller, G. K., Jr.; Riley, D. R.

1977-01-01

An experimental study was made to determine the effect on pilot performance of time delays in the visual and motion feedback loops of a simulated pursuit tracking task. Three major interrelated factors were identified: task difficulty either in the form of airplane handling qualities or target frequency, the amount and type of motion cues, and time delay itself. In general, the greater the task difficulty, the smaller the time delay that could exist without degrading pilot performance. Conversely, the greater the motion fidelity, the greater the time delay that could be tolerated. The effect of motion was, however, pilot dependent.

Application of Fourier transform infrared spectroscopy and orthogonal projections to latent structures/partial least squares regression for estimation of procyanidins average degree of polymerisation.

Science.gov (United States)

Passos, Cláudia P; Cardoso, Susana M; Barros, António S; Silva, Carlos M; Coimbra, Manuel A

2010-02-28

Fourier transform infrared (FTIR) spectroscopy has being emphasised as a widespread technique in the quick assess of food components. In this work, procyanidins were extracted with methanol and acetone/water from the seeds of white and red grape varieties. A fractionation by graded methanol/chloroform precipitations allowed to obtain 26 samples that were characterised using thiolysis as pre-treatment followed by HPLC-UV and MS detection. The average degree of polymerisation (DPn) of the procyanidins in the samples ranged from 2 to 11 flavan-3-ol residues. FTIR spectroscopy within the wavenumbers region of 1800-700 cm(-1) allowed to build a partial least squares (PLS1) regression model with 8 latent variables (LVs) for the estimation of the DPn, giving a RMSECV of 11.7%, with a R(2) of 0.91 and a RMSEP of 2.58. The application of orthogonal projection to latent structures (O-PLS1) clarifies the interpretation of the regression model vectors. Moreover, the O-PLS procedure has removed 88% of non-correlated variations with the DPn, allowing to relate the increase of the absorbance peaks at 1203 and 1099 cm(-1) with the increase of the DPn due to the higher proportion of substitutions in the aromatic ring of the polymerised procyanidin molecules. Copyright 2009 Elsevier B.V. All rights reserved.

QRank: a novel quantile regression tool for eQTL discovery.

Science.gov (United States)

Song, Xiaoyu; Li, Gen; Zhou, Zhenwei; Wang, Xianling; Ionita-Laza, Iuliana; Wei, Ying

2017-07-15

Over the past decade, there has been a remarkable improvement in our understanding of the role of genetic variation in complex human diseases, especially via genome-wide association studies. However, the underlying molecular mechanisms are still poorly characterized, impending the development of therapeutic interventions. Identifying genetic variants that influence the expression level of a gene, i.e. expression quantitative trait loci (eQTLs), can help us understand how genetic variants influence traits at the molecular level. While most eQTL studies focus on identifying mean effects on gene expression using linear regression, evidence suggests that genetic variation can impact the entire distribution of the expression level. Motivated by the potential higher order associations, several studies investigated variance eQTLs. In this paper, we develop a Quantile Rank-score based test (QRank), which provides an easy way to identify eQTLs that are associated with the conditional quantile functions of gene expression. We have applied the proposed QRank to the Genotype-Tissue Expression project, an international tissue bank for studying the relationship between genetic variation and gene expression in human tissues, and found that the proposed QRank complements the existing methods, and identifies new eQTLs with heterogeneous effects across different quantile levels. Notably, we show that the eQTLs identified by QRank but missed by linear regression are associated with greater enrichment in genome-wide significant SNPs from the GWAS catalog, and are also more likely to be tissue specific than eQTLs identified by linear regression. An R package is available on R CRAN at https://cran.r-project.org/web/packages/QRank . xs2148@cumc.columbia.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Succession of hide-seek and pursuit-evasion at heterogeneous locations.

Science.gov (United States)

Gal, Shmuel; Casas, Jérôme

2014-05-06

Many interactions between searching agents and their elusive targets are composed of a succession of steps, whether in the context of immune systems, predation or counterterrorism. In the simplest case, a two-step process starts with a search-and-hide phase, also called a hide-and-seek phase, followed by a round of pursuit-escape. Our aim is to link these two processes, usually analysed separately and with different models, in a single game theory context. We define a matrix game in which a searcher looks at a fixed number of discrete locations only once each searching for a hider, which can escape with varying probabilities according to its location. The value of the game is the overall probability of capture after k looks. The optimal search and hide strategies are described. If a searcher looks only once into any of the locations, an optimal hider chooses it's hiding place so as to make all locations equally attractive. This optimal strategy remains true as long as the number of looks is below an easily calculated threshold; however, above this threshold, the optimal position for the hider is where it has the highest probability of escaping once spotted.

Prediction of unwanted pregnancies using logistic regression, probit regression and discriminant analysis.

Science.gov (United States)

Ebrahimzadeh, Farzad; Hajizadeh, Ebrahim; Vahabi, Nasim; Almasian, Mohammad; Bakhteyar, Katayoon

2015-01-01

Unwanted pregnancy not intended by at least one of the parents has undesirable consequences for the family and the society. In the present study, three classification models were used and compared to predict unwanted pregnancies in an urban population. In this cross-sectional study, 887 pregnant mothers referring to health centers in Khorramabad, Iran, in 2012 were selected by the stratified and cluster sampling; relevant variables were measured and for prediction of unwanted pregnancy, logistic regression, discriminant analysis, and probit regression models and SPSS software version 21 were used. To compare these models, indicators such as sensitivity, specificity, the area under the ROC curve, and the percentage of correct predictions were used. The prevalence of unwanted pregnancies was 25.3%. The logistic and probit regression models indicated that parity and pregnancy spacing, contraceptive methods, household income and number of living male children were related to unwanted pregnancy. The performance of the models based on the area under the ROC curve was 0.735, 0.733, and 0.680 for logistic regression, probit regression, and linear discriminant analysis, respectively. Given the relatively high prevalence of unwanted pregnancies in Khorramabad, it seems necessary to revise family planning programs. Despite the similar accuracy of the models, if the researcher is interested in the interpretability of the results, the use of the logistic regression model is recommended.

Conflict Mediation and the Pursuit Of Happiness in the Context of Human Rights

Directory of Open Access Journals (Sweden)

Carla Maria Franco Lameira Vitale

2015-12-01

Full Text Available This current work aims to contextualize the principle of the pursuit of happiness, institute that is not legalized in the Brazilian system, but it has been used to support important decisions. It is expressly provided in several human rights diplomas and international legislation, which supports the relevance of the subject. The concept of happiness is subjective, but the fact is that the man in his universal essence, search it as a form of satisfaction and pleasure. It also intends to demonstrate that mediation, as an appropriate method of resolving conflicts and guarantor way of access to justice can be an effective instrumet to achieve the desired happiness, to the extent that those involved are encouraged to seek the best solution to satisfies the personal desires and, above all, the dignity of the human person.

In Pursuit of New Liberal Arts Education : A Project for Further Development by the Department of Intercultural Studies(新しい教養教育をもとめて-総合文化学科の取り組み-)

OpenAIRE

The Department of Intercultural Studies

2003-01-01

This is a compiled file of a college-wide symposium held by the Department of Intercultural Studies at Kobe College on March 13, 2003. Titled "in Pursuit of New Liberal Arts Education," the whole program aims to reexamine our educational ideal and practice and to further cultivate our educational potential as a department of a liberal arts college. The first part of the program consists of a couple of presentations, one by Professor Takashi Furusho and the other by Professor Tatsuru Uchida. B...

Regression and regression analysis time series prediction modeling on climate data of quetta, pakistan

International Nuclear Information System (INIS)

Jafri, Y.Z.; Kamal, L.

2007-01-01

Various statistical techniques was used on five-year data from 1998-2002 of average humidity, rainfall, maximum and minimum temperatures, respectively. The relationships to regression analysis time series (RATS) were developed for determining the overall trend of these climate parameters on the basis of which forecast models can be corrected and modified. We computed the coefficient of determination as a measure of goodness of fit, to our polynomial regression analysis time series (PRATS). The correlation to multiple linear regression (MLR) and multiple linear regression analysis time series (MLRATS) were also developed for deciphering the interdependence of weather parameters. Spearman's rand correlation and Goldfeld-Quandt test were used to check the uniformity or non-uniformity of variances in our fit to polynomial regression (PR). The Breusch-Pagan test was applied to MLR and MLRATS, respectively which yielded homoscedasticity. We also employed Bartlett's test for homogeneity of variances on a five-year data of rainfall and humidity, respectively which showed that the variances in rainfall data were not homogenous while in case of humidity, were homogenous. Our results on regression and regression analysis time series show the best fit to prediction modeling on climatic data of Quetta, Pakistan. (author)

Linear regression in astronomy. I

Science.gov (United States)

Isobe, Takashi; Feigelson, Eric D.; Akritas, Michael G.; Babu, Gutti Jogesh

1990-01-01

Five methods for obtaining linear regression fits to bivariate data with unknown or insignificant measurement errors are discussed: ordinary least-squares (OLS) regression of Y on X, OLS regression of X on Y, the bisector of the two OLS lines, orthogonal regression, and 'reduced major-axis' regression. These methods have been used by various researchers in observational astronomy, most importantly in cosmic distance scale applications. Formulas for calculating the slope and intercept coefficients and their uncertainties are given for all the methods, including a new general form of the OLS variance estimates. The accuracy of the formulas was confirmed using numerical simulations. The applicability of the procedures is discussed with respect to their mathematical properties, the nature of the astronomical data under consideration, and the scientific purpose of the regression. It is found that, for problems needing symmetrical treatment of the variables, the OLS bisector performs significantly better than orthogonal or reduced major-axis regression.

Logic regression and its extensions.

Science.gov (United States)

Schwender, Holger; Ruczinski, Ingo

2010-01-01

Logic regression is an adaptive classification and regression procedure, initially developed to reveal interacting single nucleotide polymorphisms (SNPs) in genetic association studies. In general, this approach can be used in any setting with binary predictors, when the interaction of these covariates is of primary interest. Logic regression searches for Boolean (logic) combinations of binary variables that best explain the variability in the outcome variable, and thus, reveals variables and interactions that are associated with the response and/or have predictive capabilities. The logic expressions are embedded in a generalized linear regression framework, and thus, logic regression can handle a variety of outcome types, such as binary responses in case-control studies, numeric responses, and time-to-event data. In this chapter, we provide an introduction to the logic regression methodology, list some applications in public health and medicine, and summarize some of the direct extensions and modifications of logic regression that have been proposed in the literature. Copyright © 2010 Elsevier Inc. All rights reserved.

A case of double depressor palsy followed by pursuit deficit due to sequential infarction in bilateral thalamus and right medial superior temporal area.

Science.gov (United States)

Kim, Su Jin; Yeom, Myeong In; Lee, Seung Uk

2017-12-01

We present a unique case of a patient who suffered two rare events affecting the supranuclear control, first of the vertical and second of the horizontal eye movements. The first event involved bilateral thalamic infarcts that resulted in double depressor palsy. The second event occurred 1 year later and it involved supranuclear control of horizontal eye movements creating pursuit deficit. A 47-year-old male presented with complaints of diplopia upon awakening. He had atrial fibrillation, mitral valve regurgitation, aortic valve regurgitation, and a history of spleen infarction 1 year ago. His right eye was hypertrophic and right eye downgaze was limited unilaterally of equal degree in adduction and abduction. The patient was diagnosed with double depressor palsy of the right eye. Magnetic resonance imaging (MRI) of the brain showed an old infarction of the left thalamus, and diffusion MRI showed acute infarction of the right thalamus. The patient's daily warfarin dose was 2 mg and it was increased to 5 mg with cilostazol 75 mg twice a day. Seven weeks later, the patient's ocular movement revealed near normal muscle action, and subjectively, the patient was diplopia free. At follow-up 12 months later, the patient revisited the hospital because of sudden onset of blurred vision on right gaze. He was observed to have smooth pursuit deficit to the right side, and orthophoric position of the eyes in primary gaze. MRI of the brain showed an acute infarction in the right medial superior temporal area. The patient experienced very rare abnormal eyeball movements twice. This case highlights the importance of evaluating vertical movement of the eyes and vascular supplies when patients present with depressor deficit and supports the theory of a supranuclear function in patients who present with pursuit deficit.

Tumor regression patterns in retinoblastoma

International Nuclear Information System (INIS)

Zafar, S.N.; Siddique, S.N.; Zaheer, N.

2016-01-01

To observe the types of tumor regression after treatment, and identify the common pattern of regression in our patients. Study Design: Descriptive study. Place and Duration of Study: Department of Pediatric Ophthalmology and Strabismus, Al-Shifa Trust Eye Hospital, Rawalpindi, Pakistan, from October 2011 to October 2014. Methodology: Children with unilateral and bilateral retinoblastoma were included in the study. Patients were referred to Pakistan Institute of Medical Sciences, Islamabad, for chemotherapy. After every cycle of chemotherapy, dilated funds examination under anesthesia was performed to record response of the treatment. Regression patterns were recorded on RetCam II. Results: Seventy-four tumors were included in the study. Out of 74 tumors, 3 were ICRB group A tumors, 43 were ICRB group B tumors, 14 tumors belonged to ICRB group C, and remaining 14 were ICRB group D tumors. Type IV regression was seen in 39.1% (n=29) tumors, type II in 29.7% (n=22), type III in 25.6% (n=19), and type I in 5.4% (n=4). All group A tumors (100%) showed type IV regression. Seventeen (39.5%) group B tumors showed type IV regression. In group C, 5 tumors (35.7%) showed type II regression and 5 tumors (35.7%) showed type IV regression. In group D, 6 tumors (42.9%) regressed to type II non-calcified remnants. Conclusion: The response and success of the focal and systemic treatment, as judged by the appearance of different patterns of tumor regression, varies with the ICRB grouping of the tumor. (author)

Electricity consumption forecasting in Italy using linear regression models

Energy Technology Data Exchange (ETDEWEB)

Bianco, Vincenzo; Manca, Oronzio; Nardini, Sergio [DIAM, Seconda Universita degli Studi di Napoli, Via Roma 29, 81031 Aversa (CE) (Italy)

2009-09-15

The influence of economic and demographic variables on the annual electricity consumption in Italy has been investigated with the intention to develop a long-term consumption forecasting model. The time period considered for the historical data is from 1970 to 2007. Different regression models were developed, using historical electricity consumption, gross domestic product (GDP), gross domestic product per capita (GDP per capita) and population. A first part of the paper considers the estimation of GDP, price and GDP per capita elasticities of domestic and non-domestic electricity consumption. The domestic and non-domestic short run price elasticities are found to be both approximately equal to -0.06, while long run elasticities are equal to -0.24 and -0.09, respectively. On the contrary, the elasticities of GDP and GDP per capita present higher values. In the second part of the paper, different regression models, based on co-integrated or stationary data, are presented. Different statistical tests are employed to check the validity of the proposed models. A comparison with national forecasts, based on complex econometric models, such as Markal-Time, was performed, showing that the developed regressions are congruent with the official projections, with deviations of {+-}1% for the best case and {+-}11% for the worst. These deviations are to be considered acceptable in relation to the time span taken into account. (author)

Electricity consumption forecasting in Italy using linear regression models

International Nuclear Information System (INIS)

Bianco, Vincenzo; Manca, Oronzio; Nardini, Sergio

2009-01-01

The influence of economic and demographic variables on the annual electricity consumption in Italy has been investigated with the intention to develop a long-term consumption forecasting model. The time period considered for the historical data is from 1970 to 2007. Different regression models were developed, using historical electricity consumption, gross domestic product (GDP), gross domestic product per capita (GDP per capita) and population. A first part of the paper considers the estimation of GDP, price and GDP per capita elasticities of domestic and non-domestic electricity consumption. The domestic and non-domestic short run price elasticities are found to be both approximately equal to -0.06, while long run elasticities are equal to -0.24 and -0.09, respectively. On the contrary, the elasticities of GDP and GDP per capita present higher values. In the second part of the paper, different regression models, based on co-integrated or stationary data, are presented. Different statistical tests are employed to check the validity of the proposed models. A comparison with national forecasts, based on complex econometric models, such as Markal-Time, was performed, showing that the developed regressions are congruent with the official projections, with deviations of ±1% for the best case and ±11% for the worst. These deviations are to be considered acceptable in relation to the time span taken into account. (author)

Combining Alphas via Bounded Regression

Directory of Open Access Journals (Sweden)

Zura Kakushadze

2015-11-01

Full Text Available We give an explicit algorithm and source code for combining alpha streams via bounded regression. In practical applications, typically, there is insufficient history to compute a sample covariance matrix (SCM for a large number of alphas. To compute alpha allocation weights, one then resorts to (weighted regression over SCM principal components. Regression often produces alpha weights with insufficient diversification and/or skewed distribution against, e.g., turnover. This can be rectified by imposing bounds on alpha weights within the regression procedure. Bounded regression can also be applied to stock and other asset portfolio construction. We discuss illustrative examples.

riskRegression

DEFF Research Database (Denmark)

Ozenne, Brice; Sørensen, Anne Lyngholm; Scheike, Thomas

2017-01-01

In the presence of competing risks a prediction of the time-dynamic absolute risk of an event can be based on cause-specific Cox regression models for the event and the competing risks (Benichou and Gail, 1990). We present computationally fast and memory optimized C++ functions with an R interface...... for predicting the covariate specific absolute risks, their confidence intervals, and their confidence bands based on right censored time to event data. We provide explicit formulas for our implementation of the estimator of the (stratified) baseline hazard function in the presence of tied event times. As a by...... functionals. The software presented here is implemented in the riskRegression package....

Experimental plasma research project summaries

International Nuclear Information System (INIS)

1992-06-01

This is the latest in a series of Project Summary books going back to 1976 and is the first after a hiatus of several years. They are published to provide a short description of each project supported by the Experimental Plasma Research Branch of the Division of Applied Plasma Physics in the Office of Fusion Energy. The Experimental Plasma Research Branch seeks to provide a broad range of experimental data, physics understanding, and new experimental techniques that contribute to operation, interpretation, and improvement of high temperature plasma as a source of fusion energy. In pursuit of these objectives, the branch supports research at universities, DOE laboratories, other federal laboratories and industry. About 70 percent of the funds expended are spent at universities and a significant function of this program is the training of students in fusion physics. The branch supports small- and medium-scale experimental studies directly related to specific critical plasma issues of the magnetic fusion program. Plasma physics experiments are conducted on transport of particles and energy within plasma and innovative approaches for operating, controlling, and heating plasma are evaluated for application to the larger confinement devices of the magnetic fusion program. New diagnostic approaches to measuring the properties of high temperature plasmas are developed to the point where they can be applied with confidence on the large-scale confinement experiments. Atomic data necessary for impurity control, interpretation of diagnostic data, development of heating devices, and analysis of cooling by impurity ion radiation are obtained. The project summaries are grouped into these three categories of plasma physics, diagnostic development and atomic physics

Three-dimensional nonlinear H-infinity guidance design and H-infinity-based pursuit-evasion game

Science.gov (United States)

Chen, Hsin-Yuan; Yang, Chi-Ching

2001-08-01

There are five features in this approach: (1) The complete nonlinear dynamics of the pursuit-evasion motion is considered in 3D spherical coordinate system. Neither linearization nor small signal assumptions are made. (2) The nonlinear H-infinity guidance design is derived analytically and expressed in a very simple form. (3) Unlike adaptive control concept, implementation of the proposed H(infinity ) guidance design does not need the information on target acceleration while ensuring acceptable intercept performance for arbitrary targets with the finite acceleration. (4) The derived guidance design exhibits strong robustness against variations in target acceleration. (5) Finally the issues related to the validation of the control law using Hardware In The Loop simulation are presented. The effects of the Flight Motion Simulator static and dynamic accuracies (time delay etc...) are discussed.

Regression in autistic spectrum disorders.

Science.gov (United States)

Stefanatos, Gerry A

2008-12-01

A significant proportion of children diagnosed with Autistic Spectrum Disorder experience a developmental regression characterized by a loss of previously-acquired skills. This may involve a loss of speech or social responsitivity, but often entails both. This paper critically reviews the phenomena of regression in autistic spectrum disorders, highlighting the characteristics of regression, age of onset, temporal course, and long-term outcome. Important considerations for diagnosis are discussed and multiple etiological factors currently hypothesized to underlie the phenomenon are reviewed. It is argued that regressive autistic spectrum disorders can be conceptualized on a spectrum with other regressive disorders that may share common pathophysiological features. The implications of this viewpoint are discussed.

Understanding logistic regression analysis

OpenAIRE

Sperandei, Sandro

2014-01-01

Logistic regression is used to obtain odds ratio in the presence of more than one explanatory variable. The procedure is quite similar to multiple linear regression, with the exception that the response variable is binomial. The result is the impact of each variable on the odds ratio of the observed event of interest. The main advantage is to avoid confounding effects by analyzing the association of all variables together. In this article, we explain the logistic regression procedure using ex...

TRManager – Technical Risk Manager

Directory of Open Access Journals (Sweden)

Mark A. Gregory

2009-06-01

Full Text Available This paper presents research into the development of a new information management technique called Technical Risk Manager. Project management involves the use of processes and information management techniques to aid decision making in the pursuit of project success. Project success may be achieved by meeting time, cost or performance criteria. Current project management practices focus on achieving time and cost project success criteria by using three information management techniques developed in the 1950s: Gantt, PERT and Critical Path Method. Technical Risk Manager has been developed to provide an information management technique that may be used to aid project management decision making in the pursuit of achieving the performance project success criteria.

Sparse Reconstruction of Regional Gravity Signal Based on Stabilized Orthogonal Matching Pursuit (SOMP)

Science.gov (United States)

Saadat, S. A.; Safari, A.; Needell, D.

2016-06-01

The main role of gravity field recovery is the study of dynamic processes in the interior of the Earth especially in exploration geophysics. In this paper, the Stabilized Orthogonal Matching Pursuit (SOMP) algorithm is introduced for sparse reconstruction of regional gravity signals of the Earth. In practical applications, ill-posed problems may be encountered regarding unknown parameters that are sensitive to the data perturbations. Therefore, an appropriate regularization method needs to be applied to find a stabilized solution. The SOMP algorithm aims to regularize the norm of the solution vector, while also minimizing the norm of the corresponding residual vector. In this procedure, a convergence point of the algorithm that specifies optimal sparsity-level of the problem is determined. The results show that the SOMP algorithm finds the stabilized solution for the ill-posed problem at the optimal sparsity-level, improving upon existing sparsity based approaches.

Linear regression in astronomy. II

Science.gov (United States)

Feigelson, Eric D.; Babu, Gutti J.

1992-01-01

A wide variety of least-squares linear regression procedures used in observational astronomy, particularly investigations of the cosmic distance scale, are presented and discussed. The classes of linear models considered are (1) unweighted regression lines, with bootstrap and jackknife resampling; (2) regression solutions when measurement error, in one or both variables, dominates the scatter; (3) methods to apply a calibration line to new data; (4) truncated regression models, which apply to flux-limited data sets; and (5) censored regression models, which apply when nondetections are present. For the calibration problem we develop two new procedures: a formula for the intercept offset between two parallel data sets, which propagates slope errors from one regression to the other; and a generalization of the Working-Hotelling confidence bands to nonstandard least-squares lines. They can provide improved error analysis for Faber-Jackson, Tully-Fisher, and similar cosmic distance scale relations.

A Matlab program for stepwise regression

Directory of Open Access Journals (Sweden)

Yanhong Qi

2016-03-01

Full Text Available The stepwise linear regression is a multi-variable regression for identifying statistically significant variables in the linear regression equation. In present study, we presented the Matlab program of stepwise regression.

Detrended fluctuation analysis as a regression framework: Estimating dependence at different scales

Czech Academy of Sciences Publication Activity Database

Krištoufek, Ladislav

2015-01-01

Roč. 91, č. 1 (2015), 022802-1-022802-5 ISSN 1539-3755 R&D Projects: GA ČR(CZ) GP14-11402P Grant - others:GA ČR(CZ) GAP402/11/0948 Program:GA Institutional support: RVO:67985556 Keywords : Detrended cross-correlation analysis * Regression * Scales Subject RIV: AH - Economics Impact factor: 2.288, year: 2014 http://library.utia.cas.cz/separaty/2015/E/kristoufek-0452315.pdf

Ranking the Project Management Success Factors for Construction Project in South India

Science.gov (United States)

Aneesha, K.; Haridharan, M. K.

2017-07-01

In Today’s construction industry, to achieve a greater advantage over the firms, success of each project and efficiency is required. Effective Project Management overcomes these types of challenges. This study identifies the success factors which are important for project management in construction project success. From the literature review, 26 factors were found to be critical. Project managers, construction managers, civil engineers, contractors and site engineers were the respondents. After analyzing the data in SPSS software, the dominant factors from the regression analysis are top management support, competent project team, abilities to solve problems, realistic cost and time estimates, information/communication, competency of the project manager are the 6 factors out of 12 in 26 factors. Effective communication between stakeholders got highest priority and client involvement, good leadership, clarity of project goals got second priority. Informal communication gives better results compared to formal communications like written formats. To remove communication barrier with the stakeholders, informal communication like speaking face-to-face with the language this fits for the stakeholders.

An orbital emulator for pursuit-evasion game theoretic sensor management

Science.gov (United States)

Shen, Dan; Wang, Tao; Wang, Gang; Jia, Bin; Wang, Zhonghai; Chen, Genshe; Blasch, Erik; Pham, Khanh

2017-05-01

This paper develops and evaluates an orbital emulator (OE) for space situational awareness (SSA). The OE can produce 3D satellite movements using capabilities generated from omni-wheeled robot and robotic arm motion methods. The 3D motion of a satellite is partitioned into the movements in the equatorial plane and the up-down motions in the vertical plane. The 3D actions are emulated by omni-wheeled robot models while the up-down motions are performed by a stepped-motor-controlled-ball along a rod (robotic arm), which is attached to the robot. For multiple satellites, a fast map-merging algorithm is integrated into the robot operating system (ROS) and simultaneous localization and mapping (SLAM) routines to locate the multiple robots in the scene. The OE is used to demonstrate a pursuit-evasion (PE) game theoretic sensor management algorithm, which models conflicts between a space-based-visible (SBV) satellite (as pursuer) and a geosynchronous (GEO) satellite (as evader). The cost function of the PE game is based on the informational entropy of the SBV-tracking-GEO scenario. GEO can maneuver using a continuous and low thruster. The hard-in-loop space emulator visually illustrates the SSA problem solution based PE game.

Spatial regression methods capture prediction uncertainty in species distribution model projections through time

Science.gov (United States)

Alan K. Swanson; Solomon Z. Dobrowski; Andrew O. Finley; James H. Thorne; Michael K. Schwartz

2013-01-01

The uncertainty associated with species distribution model (SDM) projections is poorly characterized, despite its potential value to decision makers. Error estimates from most modelling techniques have been shown to be biased due to their failure to account for spatial autocorrelation (SAC) of residual error. Generalized linear mixed models (GLMM) have the ability to...

Proportional Odds Logistic Regression - Effective Means of Dealing with Limited Uncertainty in Dichotomizing Clinical Outcomes

Czech Academy of Sciences Publication Activity Database

Valenta, Zdeněk; Pitha, J.; Poledne, R.

2006-01-01

Roč. 25, č. 24 (2006), s. 4227-4234 ISSN 0277-6715 R&D Projects: GA MZd NA7512 Institutional research plan: CEZ:AV0Z10300504 Keywords : proportional odds logistic regression * dichotomized outcomes * uncertainty Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 1.737, year: 2006

Quantile regression theory and applications

CERN Document Server

Davino, Cristina; Vistocco, Domenico

2013-01-01

A guide to the implementation and interpretation of Quantile Regression models This book explores the theory and numerous applications of quantile regression, offering empirical data analysis as well as the software tools to implement the methods. The main focus of this book is to provide the reader with a comprehensivedescription of the main issues concerning quantile regression; these include basic modeling, geometrical interpretation, estimation and inference for quantile regression, as well as issues on validity of the model, diagnostic tools. Each methodological aspect is explored and

Fungible weights in logistic regression.

Science.gov (United States)

Jones, Jeff A; Waller, Niels G

2016-06-01

In this article we develop methods for assessing parameter sensitivity in logistic regression models. To set the stage for this work, we first review Waller's (2008) equations for computing fungible weights in linear regression. Next, we describe 2 methods for computing fungible weights in logistic regression. To demonstrate the utility of these methods, we compute fungible logistic regression weights using data from the Centers for Disease Control and Prevention's (2010) Youth Risk Behavior Surveillance Survey, and we illustrate how these alternate weights can be used to evaluate parameter sensitivity. To make our work accessible to the research community, we provide R code (R Core Team, 2015) that will generate both kinds of fungible logistic regression weights. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

A method to the impact assessment of the returning grazing land to grassland project on regional eco-environmental vulnerability

International Nuclear Information System (INIS)

Shao, Huaiyong; Sun, Xiaofei; Wang, Haoxue; Zhang, Xiaoxue; Xiang, Zhiying; Tan, Rui; Chen, Xuanyi; Xian, Wei; Qi, Jiaguo

2016-01-01

The Chinese government has conducted the Returning Grazing Land to Grassland Project (RGLGP) across large portions of grasslands from western China since 2003. In order to explore and understand the impact in the grassland's eco-environment during the RGLGP, we utilized Projection Pursuit Model (PPM) and Geographic Information System (GIS) to develop a spatial assessment model to examine the ecological vulnerability of the grassland. Our results include five indications: (1) it is practical to apply the spatial PPM on ecological vulnerability assessment for the grassland. This methodology avoids creating an artificial hypothesis, thereby providing objective results that successfully execute a multi-index assessment process and analysis under non-linear systems in eco-environments; (2) the spatial PPM is not only capable of evaluating regional eco-environmental vulnerability in a quantitative way, but also can quantitatively demonstrate the degree of effect in each evaluation index for regional eco-environmental vulnerability; (3) the eco-environment of the Xianshui River Basin falls into the medium range level. The normalized difference vegetation index (NDVI) and land use cover and change (LUCC) crucially influence the Xianshui River Basin's eco-environmental vulnerability. Generally, in the Xianshui River Basin, regional eco-environmental conditions improved during 2000 and 2010. The RGLGP positively affected NDVI and LUCC structure, thereby promoting the enhancement of the regional eco-environment; (4) the Xianshui River Basin divides its ecological vulnerability across different levels; therefore our study investigates three ecological regions and proposes specific suggestions for each in order to assist in eco-environmental protection and rehabilitation; and lastly that (5) the spatial PPM established by this study has the potential to be applied on all types of grassland eco-environmental vulnerability assessments under the RGLGP and under the similar

A method to the impact assessment of the returning grazing land to grassland project on regional eco-environmental vulnerability

Energy Technology Data Exchange (ETDEWEB)

Shao, Huaiyong, E-mail: huaiyongshao@163.com [Key Laboratory of Geoscience Spatial Information Technology, Ministry of Land and Resources of China, Chengdu University of Technology, Chengdu 610059, Sichuan (China); Center for Global Change and Earth Observations, Michigan State University, East Lansing 48823, MI (United States); Sun, Xiaofei; Wang, Haoxue; Zhang, Xiaoxue [Key Laboratory of Geoscience Spatial Information Technology, Ministry of Land and Resources of China, Chengdu University of Technology, Chengdu 610059, Sichuan (China); Xiang, Zhiying [School of Earth Sciences, Zhejiang University, Hangzhou 310027, Zhejiang (China); Tan, Rui; Chen, Xuanyi [Key Laboratory of Geoscience Spatial Information Technology, Ministry of Land and Resources of China, Chengdu University of Technology, Chengdu 610059, Sichuan (China); Xian, Wei [College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225, Sichuan (China); Qi, Jiaguo [Center for Global Change and Earth Observations, Michigan State University, East Lansing 48823, MI (United States)

2016-01-15

The Chinese government has conducted the Returning Grazing Land to Grassland Project (RGLGP) across large portions of grasslands from western China since 2003. In order to explore and understand the impact in the grassland's eco-environment during the RGLGP, we utilized Projection Pursuit Model (PPM) and Geographic Information System (GIS) to develop a spatial assessment model to examine the ecological vulnerability of the grassland. Our results include five indications: (1) it is practical to apply the spatial PPM on ecological vulnerability assessment for the grassland. This methodology avoids creating an artificial hypothesis, thereby providing objective results that successfully execute a multi-index assessment process and analysis under non-linear systems in eco-environments; (2) the spatial PPM is not only capable of evaluating regional eco-environmental vulnerability in a quantitative way, but also can quantitatively demonstrate the degree of effect in each evaluation index for regional eco-environmental vulnerability; (3) the eco-environment of the Xianshui River Basin falls into the medium range level. The normalized difference vegetation index (NDVI) and land use cover and change (LUCC) crucially influence the Xianshui River Basin's eco-environmental vulnerability. Generally, in the Xianshui River Basin, regional eco-environmental conditions improved during 2000 and 2010. The RGLGP positively affected NDVI and LUCC structure, thereby promoting the enhancement of the regional eco-environment; (4) the Xianshui River Basin divides its ecological vulnerability across different levels; therefore our study investigates three ecological regions and proposes specific suggestions for each in order to assist in eco-environmental protection and rehabilitation; and lastly that (5) the spatial PPM established by this study has the potential to be applied on all types of grassland eco-environmental vulnerability assessments under the RGLGP and under the

Project Based Learning: In Pursuit of Androgogic Effectiveness

Science.gov (United States)

Ntombela, Berrington X. S.

2015-01-01

In an attempt to standardise Foundation Programmes for Oman higher education providers, the Oman Academic Standards for General Foundation Programmes stipulated that higher education providers should offer programmes that ensure androgogic effectiveness. In the light of that, this paper presents attempts by a University College in Oman to…

Regression analysis: An evaluation of the inuences behindthe pricing of beer

OpenAIRE

Eriksson, Sara; Häggmark, Jonas

2017-01-01

This bachelor thesis in applied mathematics is an analysis of which factors affect the pricing of beer at the Swedish market. A multiple linear regression model is created with the statistical programming language R through a study of the influences for several explanatory variables. For example these variables include country of origin, beer style, volume sold and a Bayesian weighted mean rating from RateBeer, a popular website for beer enthusiasts. The main goal of the project is to find si...

The pursuit of quantum gravity. Memoirs of Bryce DeWitt from 1946 to 2004

International Nuclear Information System (INIS)

DeWitt-Morette, Cecile

2011-01-01

1946 is the year Bryce DeWitt entered Harvard graduate school. Quantum Gravity was his goal and remained his goal throughout his lifetime until the very end. The pursuit of Quantum Gravity requires a profound understanding of Quantum Physics and Gravitation Physics. As G. A. Vilkovisky commented, ''Quantum Gravity is a combination of two words, and one should know both. Bryce understood this as nobody else, and this wisdom is completely unknown to many authors of the flux of papers that we see nowadays.'' Distinguished physicist Cecile DeWitt-Morette skillfully blends her personal and scientific account with a wealth of her late husband's often unpublished writings on the subject matter. This volume, through the perspective of the leading researcher on quantum gravity of his generation, will provide an invaluable source of reference for anyone working in the field. (orig.)

Principal component regression analysis with SPSS.

Science.gov (United States)

Liu, R X; Kuang, J; Gong, Q; Hou, X L

2003-06-01

The paper introduces all indices of multicollinearity diagnoses, the basic principle of principal component regression and determination of 'best' equation method. The paper uses an example to describe how to do principal component regression analysis with SPSS 10.0: including all calculating processes of the principal component regression and all operations of linear regression, factor analysis, descriptives, compute variable and bivariate correlations procedures in SPSS 10.0. The principal component regression analysis can be used to overcome disturbance of the multicollinearity. The simplified, speeded up and accurate statistical effect is reached through the principal component regression analysis with SPSS.

A Fast Gradient Method for Nonnegative Sparse Regression With Self-Dictionary

Science.gov (United States)

Gillis, Nicolas; Luce, Robert

2018-01-01

A nonnegative matrix factorization (NMF) can be computed efficiently under the separability assumption, which asserts that all the columns of the given input data matrix belong to the cone generated by a (small) subset of them. The provably most robust methods to identify these conic basis columns are based on nonnegative sparse regression and self dictionaries, and require the solution of large-scale convex optimization problems. In this paper we study a particular nonnegative sparse regression model with self dictionary. As opposed to previously proposed models, this model yields a smooth optimization problem where the sparsity is enforced through linear constraints. We show that the Euclidean projection on the polyhedron defined by these constraints can be computed efficiently, and propose a fast gradient method to solve our model. We compare our algorithm with several state-of-the-art methods on synthetic data sets and real-world hyperspectral images.

Immanent Politics, Participatory Democracy, and the Pursuit of Eudaimonia

Directory of Open Access Journals (Sweden)

Geoffrey Allan Plauché

2011-06-01

Full Text Available This paper builds on the burgeoning tradition of Aristotelian liberalism. It identifies and critiques a fundamental inequality inherent in the nature of the state and, in particular, the liberal representative-democratic state: namely, an institutionalized inequality in authority. The analysis draws on and synthesizes disparate philosophical and political traditions: Aristotle’s virtue ethics and politics, Locke’s natural rights and idea of equality in authority in the state of nature (sans state of nature, the New Left’s conception of participatory democracy (particularly as described in a number of under-utilized essays by Murray Rothbard and Don Lavoie, and philosophical anarchism. The deleterious consequences of this fundamental institutionalized inequality are explored, including on social justice and economic progress, on individual autonomy, on direct and meaningful civic and political participation, and the creation and maintenance of other artificial inequalities as well as the exacerbation of natural inequalities (economic and others. In the process, the paper briefly sketches a neo-Aristotelian theory of virtue ethics and natural individual rights, for which the principle of equal and total liberty for all is of fundamental political importance. And, finally, a non-statist conception of politics is developed, with politics defined as discourse and deliberation between equals (in authority in joint pursuit of eudaimonia (flourishing, well-being.[Note: The following font file may be useful for viewing the Greek characters in the Word file above: SPIONIC_.TTF.

Fast Component Pursuit for Large-Scale Inverse Covariance Estimation.

Science.gov (United States)

Han, Lei; Zhang, Yu; Zhang, Tong

2016-08-01

The maximum likelihood estimation (MLE) for the Gaussian graphical model, which is also known as the inverse covariance estimation problem, has gained increasing interest recently. Most existing works assume that inverse covariance estimators contain sparse structure and then construct models with the ℓ 1 regularization. In this paper, different from existing works, we study the inverse covariance estimation problem from another perspective by efficiently modeling the low-rank structure in the inverse covariance, which is assumed to be a combination of a low-rank part and a diagonal matrix. One motivation for this assumption is that the low-rank structure is common in many applications including the climate and financial analysis, and another one is that such assumption can reduce the computational complexity when computing its inverse. Specifically, we propose an efficient COmponent Pursuit (COP) method to obtain the low-rank part, where each component can be sparse. For optimization, the COP method greedily learns a rank-one component in each iteration by maximizing the log-likelihood. Moreover, the COP algorithm enjoys several appealing properties including the existence of an efficient solution in each iteration and the theoretical guarantee on the convergence of this greedy approach. Experiments on large-scale synthetic and real-world datasets including thousands of millions variables show that the COP method is faster than the state-of-the-art techniques for the inverse covariance estimation problem when achieving comparable log-likelihood on test data.

Cost effectiveness of eptifibatide in acute coronary syndromes; an economic analysis of Western European patients enrolled in the PURSUIT trial. The Platelet IIa/IIb in unstable Angina: Receptor Suppression Using Integrilin Therapy.

Science.gov (United States)

Brown, R E; Henderson, R A; Koster, D; Hutton, J; Simoons, M L

2002-01-01

To assess the direct medical costs and cost effectiveness of routine eptifibatide use amongst patients with unstable angina and myocardial infarction without persistent ST-segment elevation in the Western European subgroup of the PURSUIT trial. Health care resources were collected for the Western European PURSUIT trial patients (n=3697). Unit costs for major resources were developed within six countries using a consistent bottom-up methodology. Resource consumption from the Western European population was used to calculate the average direct medical costs per patient in the eptifibatide and placebo arms of the trial. Eptifibatide was estimated to cost 524 Euros per treatment. Long-term survival estimated from the 6-month trial survival data and combined with the cost data was used to calculate cost-effectiveness ratios. Additionally, cost per death and non-fatal myocardial infarction at 30 days was calculated. Sensitivity analyses were conducted on the discount rate and resource consumption. Cost-effectiveness ratios ranged from 9603 Euros to 18 115 Euros per year of life saved with 3% discount. Using resource consumption based on countries with low coronary arteriography rates, the cost per year of life saved was between 3329 Euros and 10 079 Euros. Using resource consumption based on high coronary arteriography rate countries, the cost per year of life saved was between 17 089 Euros and 24 099 Euros. Assuming no difference in treatment costs except for the addition of eptifibatide, the incremental cost per year of life saved was 23 818 Euros. Routine eptifibatide use was associated with a reduction in the combined end-point of death and myocardial infarction at 30 days, which was sustained at 6 months. Long-term projections indicate a modest increase in survival in eptifibatide patients. These data translate into cost-effectiveness ratios that compare favourably with other new technologies that are currently in use. Copyright 2001 The European Society of

Logistic regression models

CERN Document Server

Hilbe, Joseph M

2009-01-01

This book really does cover everything you ever wanted to know about logistic regression … with updates available on the author's website. Hilbe, a former national athletics champion, philosopher, and expert in astronomy, is a master at explaining statistical concepts and methods. Readers familiar with his other expository work will know what to expect-great clarity.The book provides considerable detail about all facets of logistic regression. No step of an argument is omitted so that the book will meet the needs of the reader who likes to see everything spelt out, while a person familiar with some of the topics has the option to skip "obvious" sections. The material has been thoroughly road-tested through classroom and web-based teaching. … The focus is on helping the reader to learn and understand logistic regression. The audience is not just students meeting the topic for the first time, but also experienced users. I believe the book really does meet the author's goal … .-Annette J. Dobson, Biometric...

Logistic regression applied to natural hazards: rare event logistic regression with replications

Science.gov (United States)

Guns, M.; Vanacker, V.

2012-06-01

Statistical analysis of natural hazards needs particular attention, as most of these phenomena are rare events. This study shows that the ordinary rare event logistic regression, as it is now commonly used in geomorphologic studies, does not always lead to a robust detection of controlling factors, as the results can be strongly sample-dependent. In this paper, we introduce some concepts of Monte Carlo simulations in rare event logistic regression. This technique, so-called rare event logistic regression with replications, combines the strength of probabilistic and statistical methods, and allows overcoming some of the limitations of previous developments through robust variable selection. This technique was here developed for the analyses of landslide controlling factors, but the concept is widely applicable for statistical analyses of natural hazards.

Understanding logistic regression analysis.

Science.gov (United States)

Sperandei, Sandro

2014-01-01

Logistic regression is used to obtain odds ratio in the presence of more than one explanatory variable. The procedure is quite similar to multiple linear regression, with the exception that the response variable is binomial. The result is the impact of each variable on the odds ratio of the observed event of interest. The main advantage is to avoid confounding effects by analyzing the association of all variables together. In this article, we explain the logistic regression procedure using examples to make it as simple as possible. After definition of the technique, the basic interpretation of the results is highlighted and then some special issues are discussed.

An ensemble based nonlinear orthogonal matching pursuit algorithm for sparse history matching of reservoir models

KAUST Repository

Fsheikh, Ahmed H.

2013-01-01

A nonlinear orthogonal matching pursuit (NOMP) for sparse calibration of reservoir models is presented. Sparse calibration is a challenging problem as the unknowns are both the non-zero components of the solution and their associated weights. NOMP is a greedy algorithm that discovers at each iteration the most correlated components of the basis functions with the residual. The discovered basis (aka support) is augmented across the nonlinear iterations. Once the basis functions are selected from the dictionary, the solution is obtained by applying Tikhonov regularization. The proposed algorithm relies on approximate gradient estimation using an iterative stochastic ensemble method (ISEM). ISEM utilizes an ensemble of directional derivatives to efficiently approximate gradients. In the current study, the search space is parameterized using an overcomplete dictionary of basis functions built using the K-SVD algorithm.

ICNC2003: Proceedings of the seventh international conference on nuclear criticality safety. Challenges in the pursuit of global nuclear criticality safety

International Nuclear Information System (INIS)

2003-10-01

This proceedings contain (technical, oral and poster papers) presented papers at the Seventh International Conference on Nuclear Criticality Safety ICNC2003 held on 20-24 October 2003, in Tokai, Ibaraki, Japan, following ICNC'99 in Versailles, France. The theme of this conference is 'Challenges in the Pursuit of Global Nuclear Criticality Safety'. This proceedings represent the current status of nuclear criticality safety research throughout the world. The 81 of the presented papers are indexed individually. (J.P.N.)

ICNC2003: Proceedings of the seventh international conference on nuclear criticality safety. Challenges in the pursuit of global nuclear criticality safety

International Nuclear Information System (INIS)

2003-10-01

This proceedings contain (technical, oral and poster papers) presented papers at the Seventh International Conference on Nuclear Criticality Safety ICNC2003 held on 20-24 October 2003, in Tokai, Ibaraki, Japan, following ICNC'99 in Versailles, France. The theme of this conference is 'Challenges in the Pursuit of Global Nuclear Criticality Safety'. This proceedings represent the current status of nuclear criticality safety research throughout the world. The 79 of the presented papers are indexed individually. (J.P.N.)

Minimax Regression Quantiles

DEFF Research Database (Denmark)

Bache, Stefan Holst

A new and alternative quantile regression estimator is developed and it is shown that the estimator is root n-consistent and asymptotically normal. The estimator is based on a minimax ‘deviance function’ and has asymptotically equivalent properties to the usual quantile regression estimator. It is......, however, a different and therefore new estimator. It allows for both linear- and nonlinear model specifications. A simple algorithm for computing the estimates is proposed. It seems to work quite well in practice but whether it has theoretical justification is still an open question....

Regression with Sparse Approximations of Data

DEFF Research Database (Denmark)

Noorzad, Pardis; Sturm, Bob L.

2012-01-01

We propose sparse approximation weighted regression (SPARROW), a method for local estimation of the regression function that uses sparse approximation with a dictionary of measurements. SPARROW estimates the regression function at a point with a linear combination of a few regressands selected...... by a sparse approximation of the point in terms of the regressors. We show SPARROW can be considered a variant of \\(k\\)-nearest neighbors regression (\\(k\\)-NNR), and more generally, local polynomial kernel regression. Unlike \\(k\\)-NNR, however, SPARROW can adapt the number of regressors to use based...

Logistic regression applied to natural hazards: rare event logistic regression with replications

Directory of Open Access Journals (Sweden)

M. Guns

2012-06-01

Full Text Available Statistical analysis of natural hazards needs particular attention, as most of these phenomena are rare events. This study shows that the ordinary rare event logistic regression, as it is now commonly used in geomorphologic studies, does not always lead to a robust detection of controlling factors, as the results can be strongly sample-dependent. In this paper, we introduce some concepts of Monte Carlo simulations in rare event logistic regression. This technique, so-called rare event logistic regression with replications, combines the strength of probabilistic and statistical methods, and allows overcoming some of the limitations of previous developments through robust variable selection. This technique was here developed for the analyses of landslide controlling factors, but the concept is widely applicable for statistical analyses of natural hazards.

A simple approach to power and sample size calculations in logistic regression and Cox regression models.

Science.gov (United States)

Vaeth, Michael; Skovlund, Eva

2004-06-15

For a given regression problem it is possible to identify a suitably defined equivalent two-sample problem such that the power or sample size obtained for the two-sample problem also applies to the regression problem. For a standard linear regression model the equivalent two-sample problem is easily identified, but for generalized linear models and for Cox regression models the situation is more complicated. An approximately equivalent two-sample problem may, however, also be identified here. In particular, we show that for logistic regression and Cox regression models the equivalent two-sample problem is obtained by selecting two equally sized samples for which the parameters differ by a value equal to the slope times twice the standard deviation of the independent variable and further requiring that the overall expected number of events is unchanged. In a simulation study we examine the validity of this approach to power calculations in logistic regression and Cox regression models. Several different covariate distributions are considered for selected values of the overall response probability and a range of alternatives. For the Cox regression model we consider both constant and non-constant hazard rates. The results show that in general the approach is remarkably accurate even in relatively small samples. Some discrepancies are, however, found in small samples with few events and a highly skewed covariate distribution. Comparison with results based on alternative methods for logistic regression models with a single continuous covariate indicates that the proposed method is at least as good as its competitors. The method is easy to implement and therefore provides a simple way to extend the range of problems that can be covered by the usual formulas for power and sample size determination. Copyright 2004 John Wiley & Sons, Ltd.

A model record of technologies for use in a compatible projects for environmental licensing of wind farms; Um modelo de registro das tecnologias para uso na compatibilizacao de projetos para licenciamento ambiental de parques eolicos

Energy Technology Data Exchange (ETDEWEB)

Tavares Junior, Wandemberg; Oliveira, Lucia Maria Barbosa [Universidade de Fortaleza (UNIFOR), CE (Brazil)

2008-07-01

This article presents the development of a model for survey and registration of technologies that can be inserted in the process of reconciliation of the subjects of the project for environmental licensing of wind farms. It was used a basis for the theoretical model of the Simultaneous Engineering and Failure Mode and Effect Analysis - FMEA. Given the importance that the wind has for the pursuit of sustainable development, this work had as its main objective to contribute to the reduction of negative indices, proposing improvements to the process of project for environmental licensing of wind farms. (author)

Personal ways of handling everyday life

DEFF Research Database (Denmark)

Jensen, Lasse Meinert

at variations in everyday life pursuits:  How does a person's pursuit of goals and concerns lead him/her to experience and handle breaks, interruptions, and variation in everyday activities?  The research project so far holds quantitative data.  A convenient sample of 217 persons were administered...

Project Documentation as a Risk for Public Projects

Directory of Open Access Journals (Sweden)

Vladěna Štěpánková

2015-08-01

Full Text Available Purpose of the article: The paper presents the different methodologies used for creating documentation and focuses on public projects and their requirements for this documentation. Since documentation is also incorporated in the overall planning of the project and its duration is estimated using expert qualified estimate, can any change in this documentation lead to project delays, or increase its cost as a result of consuming administration, and therefore the documentation is seen as a risk, which may threaten the project as a public contract by which a company trying to achieve and obtains it, and generally any project. Methodology/methods: There are used methods of obtaining information in this paper. These are mainly structured interviews in combination with a brainstorming, furthermore also been used questionnaire for companies dealing with public procurement. As a data processing program was used MS Excel and basic statistical methods based on regression analysis. Scientific aim: The article deals with the construction market in the Czech Republic and examines the impact of changes in project documentation of public projects on their turnover. Findings: In this paper we summarize the advantages and disadvantages of having project documentation. In the case of public contracts and changes in legislation it is necessary to focus on creating documentation in advance, follow the new requirements and try to reach them in the shortest possible time. Conclusions: The paper concludes with recommendations on how to proceed, if these changes and how to reduce costs, which may cause the risk of documentation.

Evaluating the effect of a third-party implementation of resolution recovery on the quality of SPECT bone scan imaging using visual grading regression.

Science.gov (United States)

Hay, Peter D; Smith, Julie; O'Connor, Richard A

2016-02-01

The aim of this study was to evaluate the benefits to SPECT bone scan image quality when applying resolution recovery (RR) during image reconstruction using software provided by a third-party supplier. Bone SPECT data from 90 clinical studies were reconstructed retrospectively using software supplied independent of the gamma camera manufacturer. The current clinical datasets contain 120×10 s projections and are reconstructed using an iterative method with a Butterworth postfilter. Five further reconstructions were created with the following characteristics: 10 s projections with a Butterworth postfilter (to assess intraobserver variation); 10 s projections with a Gaussian postfilter with and without RR; and 5 s projections with a Gaussian postfilter with and without RR. Two expert observers were asked to rate image quality on a five-point scale relative to our current clinical reconstruction. Datasets were anonymized and presented in random order. The benefits of RR on image scores were evaluated using ordinal logistic regression (visual grading regression). The application of RR during reconstruction increased the probability of both observers of scoring image quality as better than the current clinical reconstruction even where the dataset contained half the normal counts. Type of reconstruction and observer were both statistically significant variables in the ordinal logistic regression model. Visual grading regression was found to be a useful method for validating the local introduction of technological developments in nuclear medicine imaging. RR, as implemented by the independent software supplier, improved bone SPECT image quality when applied during image reconstruction. In the majority of clinical cases, acquisition times for bone SPECT intended for the purposes of localization can safely be halved (from 10 s projections to 5 s) when RR is applied.

Post-processing through linear regression

Science.gov (United States)

van Schaeybroeck, B.; Vannitsem, S.

2011-03-01

Various post-processing techniques are compared for both deterministic and ensemble forecasts, all based on linear regression between forecast data and observations. In order to evaluate the quality of the regression methods, three criteria are proposed, related to the effective correction of forecast error, the optimal variability of the corrected forecast and multicollinearity. The regression schemes under consideration include the ordinary least-square (OLS) method, a new time-dependent Tikhonov regularization (TDTR) method, the total least-square method, a new geometric-mean regression (GM), a recently introduced error-in-variables (EVMOS) method and, finally, a "best member" OLS method. The advantages and drawbacks of each method are clarified. These techniques are applied in the context of the 63 Lorenz system, whose model version is affected by both initial condition and model errors. For short forecast lead times, the number and choice of predictors plays an important role. Contrarily to the other techniques, GM degrades when the number of predictors increases. At intermediate lead times, linear regression is unable to provide corrections to the forecast and can sometimes degrade the performance (GM and the best member OLS with noise). At long lead times the regression schemes (EVMOS, TDTR) which yield the correct variability and the largest correlation between ensemble error and spread, should be preferred.

X-rays of inner worlds: the mid-twentieth-century American projective test movement.

Science.gov (United States)

Lemov, Rebecca

2011-01-01

This essay begins to tell the neglected history of the projective test movement in the U.S. behavioral sciences from approximately 1941 to 1968. This cross-disciplinary enterprise attempted to use projective techniques as "X-ray" machines to see into the psyches of subjects tested around the world. The aim was to gather subjective materials en masse, pursuing data on a scope, scale, and manner rarely hazarded before in any science. In particular, the targeted data included the traces of the inner life and elusive aspects of subjective experience including dreams, life stories, and myriad test results from a battery of tests. This essay explores how the movement and the experimental data bank that resulted were unlikely yet telling sites for the practice and pursuit of the Cold War human sciences. To look closely at the encounters that resulted is to show how the most out-of-the-way places and seemingly insignificant moments played a role in heady scientific ambitions and global geopolitical projects. At times, the projective test movement became a mirror of Cold War rationality itself, as tests were employed at the very limits of their possible extension. The essay argues for an off-kilter centrality in the movement itself, shedding light on the would-be unified social sciences after World War II and the "subjective turn" they took. © 2011 Wiley Periodicals, Inc.

Regression modeling methods, theory, and computation with SAS

CERN Document Server

Panik, Michael

2009-01-01

Regression Modeling: Methods, Theory, and Computation with SAS provides an introduction to a diverse assortment of regression techniques using SAS to solve a wide variety of regression problems. The author fully documents the SAS programs and thoroughly explains the output produced by the programs.The text presents the popular ordinary least squares (OLS) approach before introducing many alternative regression methods. It covers nonparametric regression, logistic regression (including Poisson regression), Bayesian regression, robust regression, fuzzy regression, random coefficients regression,

Better Autologistic Regression

Directory of Open Access Journals (Sweden)

Mark A. Wolters

2017-11-01

Full Text Available Autologistic regression is an important probability model for dichotomous random variables observed along with covariate information. It has been used in various fields for analyzing binary data possessing spatial or network structure. The model can be viewed as an extension of the autologistic model (also known as the Ising model, quadratic exponential binary distribution, or Boltzmann machine to include covariates. It can also be viewed as an extension of logistic regression to handle responses that are not independent. Not all authors use exactly the same form of the autologistic regression model. Variations of the model differ in two respects. First, the variable coding—the two numbers used to represent the two possible states of the variables—might differ. Common coding choices are (zero, one and (minus one, plus one. Second, the model might appear in either of two algebraic forms: a standard form, or a recently proposed centered form. Little attention has been paid to the effect of these differences, and the literature shows ambiguity about their importance. It is shown here that changes to either coding or centering in fact produce distinct, non-nested probability models. Theoretical results, numerical studies, and analysis of an ecological data set all show that the differences among the models can be large and practically significant. Understanding the nature of the differences and making appropriate modeling choices can lead to significantly improved autologistic regression analyses. The results strongly suggest that the standard model with plus/minus coding, which we call the symmetric autologistic model, is the most natural choice among the autologistic variants.

Semiparametric regression during 2003–2007

KAUST Repository

Ruppert, David; Wand, M.P.; Carroll, Raymond J.

2009-01-01

Semiparametric regression is a fusion between parametric regression and nonparametric regression that integrates low-rank penalized splines, mixed model and hierarchical Bayesian methodology – thus allowing more streamlined handling of longitudinal and spatial correlation. We review progress in the field over the five-year period between 2003 and 2007. We find semiparametric regression to be a vibrant field with substantial involvement and activity, continual enhancement and widespread application.

Unbalanced Regressions and the Predictive Equation

DEFF Research Database (Denmark)

Osterrieder, Daniela; Ventosa-Santaulària, Daniel; Vera-Valdés, J. Eduardo

Predictive return regressions with persistent regressors are typically plagued by (asymptotically) biased/inconsistent estimates of the slope, non-standard or potentially even spurious statistical inference, and regression unbalancedness. We alleviate the problem of unbalancedness in the theoreti......Predictive return regressions with persistent regressors are typically plagued by (asymptotically) biased/inconsistent estimates of the slope, non-standard or potentially even spurious statistical inference, and regression unbalancedness. We alleviate the problem of unbalancedness...

Comparison of multinomial logistic regression and logistic regression: which is more efficient in allocating land use?

Science.gov (United States)

Lin, Yingzhi; Deng, Xiangzheng; Li, Xing; Ma, Enjun

2014-12-01

Spatially explicit simulation of land use change is the basis for estimating the effects of land use and cover change on energy fluxes, ecology and the environment. At the pixel level, logistic regression is one of the most common approaches used in spatially explicit land use allocation models to determine the relationship between land use and its causal factors in driving land use change, and thereby to evaluate land use suitability. However, these models have a drawback in that they do not determine/allocate land use based on the direct relationship between land use change and its driving factors. Consequently, a multinomial logistic regression method was introduced to address this flaw, and thereby, judge the suitability of a type of land use in any given pixel in a case study area of the Jiangxi Province, China. A comparison of the two regression methods indicated that the proportion of correctly allocated pixels using multinomial logistic regression was 92.98%, which was 8.47% higher than that obtained using logistic regression. Paired t-test results also showed that pixels were more clearly distinguished by multinomial logistic regression than by logistic regression. In conclusion, multinomial logistic regression is a more efficient and accurate method for the spatial allocation of land use changes. The application of this method in future land use change studies may improve the accuracy of predicting the effects of land use and cover change on energy fluxes, ecology, and environment.

Interpretation of commonly used statistical regression models.

Science.gov (United States)

Kasza, Jessica; Wolfe, Rory

2014-01-01

A review of some regression models commonly used in respiratory health applications is provided in this article. Simple linear regression, multiple linear regression, logistic regression and ordinal logistic regression are considered. The focus of this article is on the interpretation of the regression coefficients of each model, which are illustrated through the application of these models to a respiratory health research study. © 2013 The Authors. Respirology © 2013 Asian Pacific Society of Respirology.

Linear regression

CERN Document Server

Olive, David J

2017-01-01

This text covers both multiple linear regression and some experimental design models. The text uses the response plot to visualize the model and to detect outliers, does not assume that the error distribution has a known parametric distribution, develops prediction intervals that work when the error distribution is unknown, suggests bootstrap hypothesis tests that may be useful for inference after variable selection, and develops prediction regions and large sample theory for the multivariate linear regression model that has m response variables. A relationship between multivariate prediction regions and confidence regions provides a simple way to bootstrap confidence regions. These confidence regions often provide a practical method for testing hypotheses. There is also a chapter on generalized linear models and generalized additive models. There are many R functions to produce response and residual plots, to simulate prediction intervals and hypothesis tests, to detect outliers, and to choose response trans...

Regression modeling of ground-water flow

Science.gov (United States)

Cooley, R.L.; Naff, R.L.

1985-01-01

Nonlinear multiple regression methods are developed to model and analyze groundwater flow systems. Complete descriptions of regression methodology as applied to groundwater flow models allow scientists and engineers engaged in flow modeling to apply the methods to a wide range of problems. Organization of the text proceeds from an introduction that discusses the general topic of groundwater flow modeling, to a review of basic statistics necessary to properly apply regression techniques, and then to the main topic: exposition and use of linear and nonlinear regression to model groundwater flow. Statistical procedures are given to analyze and use the regression models. A number of exercises and answers are included to exercise the student on nearly all the methods that are presented for modeling and statistical analysis. Three computer programs implement the more complex methods. These three are a general two-dimensional, steady-state regression model for flow in an anisotropic, heterogeneous porous medium, a program to calculate a measure of model nonlinearity with respect to the regression parameters, and a program to analyze model errors in computed dependent variables such as hydraulic head. (USGS)

Thresholding projection estimators in functional linear models

OpenAIRE

Cardot, Hervé; Johannes, Jan

2010-01-01

We consider the problem of estimating the regression function in functional linear regression models by proposing a new type of projection estimators which combine dimension reduction and thresholding. The introduction of a threshold rule allows to get consistency under broad assumptions as well as minimax rates of convergence under additional regularity hypotheses. We also consider the particular case of Sobolev spaces generated by the trigonometric basis which permits to get easily mean squ...

Post-processing through linear regression

Directory of Open Access Journals (Sweden)

B. Van Schaeybroeck

2011-03-01

Full Text Available Various post-processing techniques are compared for both deterministic and ensemble forecasts, all based on linear regression between forecast data and observations. In order to evaluate the quality of the regression methods, three criteria are proposed, related to the effective correction of forecast error, the optimal variability of the corrected forecast and multicollinearity. The regression schemes under consideration include the ordinary least-square (OLS method, a new time-dependent Tikhonov regularization (TDTR method, the total least-square method, a new geometric-mean regression (GM, a recently introduced error-in-variables (EVMOS method and, finally, a "best member" OLS method. The advantages and drawbacks of each method are clarified.

These techniques are applied in the context of the 63 Lorenz system, whose model version is affected by both initial condition and model errors. For short forecast lead times, the number and choice of predictors plays an important role. Contrarily to the other techniques, GM degrades when the number of predictors increases. At intermediate lead times, linear regression is unable to provide corrections to the forecast and can sometimes degrade the performance (GM and the best member OLS with noise. At long lead times the regression schemes (EVMOS, TDTR which yield the correct variability and the largest correlation between ensemble error and spread, should be preferred.

TH-D-204-00: The Pursuit of Radiation Oncology Performance Excellence

International Nuclear Information System (INIS)

2016-01-01

The Malcolm Baldrige National Quality Improvement Act was signed into law in 1987 to advance U.S. business competitiveness and economic growth. Administered by the National Institute of Standards and Technology NIST, the Act created the Baldrige National Quality Program, now renamed the Baldrige Performance Excellence Program. The comprehensive analytical approaches referred to as the Baldrige Healthcare Criteria, are very well suited for the evaluation and sustainable improvement of radiation oncology management and operations. A multidisciplinary self-assessment approach is used for radiotherapy program evaluation and development in order to generate a fact based knowledge driven system for improving quality of care, increasing patient satisfaction, building employee engagement, and boosting organizational innovation. The methodology also provides a valuable framework for benchmarking an individual radiation oncology practice against guidelines defined by accreditation and professional organizations and regulatory agencies. Learning Objectives: To gain knowledge of the Baldrige Performance Excellence Program as it relates to Radiation Oncology. To appreciate the value of a multidisciplinary self-assessment approach in the pursuit of Radiation Oncology quality care, patient satisfaction, and workforce commitment. To acquire a set of useful measurement tools with which an individual Radiation Oncology practice can benchmark its performance against guidelines defined by accreditation and professional organizations and regulatory agencies.

TH-D-204-01: The Pursuit of Radiation Oncology Performance Excellence

Energy Technology Data Exchange (ETDEWEB)

Sternick, E. [The Warren Alpert Medical School of Brown Univ., Providence, RI (United States)

2016-06-15

The Malcolm Baldrige National Quality Improvement Act was signed into law in 1987 to advance U.S. business competitiveness and economic growth. Administered by the National Institute of Standards and Technology NIST, the Act created the Baldrige National Quality Program, now renamed the Baldrige Performance Excellence Program. The comprehensive analytical approaches referred to as the Baldrige Healthcare Criteria, are very well suited for the evaluation and sustainable improvement of radiation oncology management and operations. A multidisciplinary self-assessment approach is used for radiotherapy program evaluation and development in order to generate a fact based knowledge driven system for improving quality of care, increasing patient satisfaction, building employee engagement, and boosting organizational innovation. The methodology also provides a valuable framework for benchmarking an individual radiation oncology practice against guidelines defined by accreditation and professional organizations and regulatory agencies. Learning Objectives: To gain knowledge of the Baldrige Performance Excellence Program as it relates to Radiation Oncology. To appreciate the value of a multidisciplinary self-assessment approach in the pursuit of Radiation Oncology quality care, patient satisfaction, and workforce commitment. To acquire a set of useful measurement tools with which an individual Radiation Oncology practice can benchmark its performance against guidelines defined by accreditation and professional organizations and regulatory agencies.

TH-D-204-00: The Pursuit of Radiation Oncology Performance Excellence

Energy Technology Data Exchange (ETDEWEB)

NONE

2016-06-15

The Malcolm Baldrige National Quality Improvement Act was signed into law in 1987 to advance U.S. business competitiveness and economic growth. Administered by the National Institute of Standards and Technology NIST, the Act created the Baldrige National Quality Program, now renamed the Baldrige Performance Excellence Program. The comprehensive analytical approaches referred to as the Baldrige Healthcare Criteria, are very well suited for the evaluation and sustainable improvement of radiation oncology management and operations. A multidisciplinary self-assessment approach is used for radiotherapy program evaluation and development in order to generate a fact based knowledge driven system for improving quality of care, increasing patient satisfaction, building employee engagement, and boosting organizational innovation. The methodology also provides a valuable framework for benchmarking an individual radiation oncology practice against guidelines defined by accreditation and professional organizations and regulatory agencies. Learning Objectives: To gain knowledge of the Baldrige Performance Excellence Program as it relates to Radiation Oncology. To appreciate the value of a multidisciplinary self-assessment approach in the pursuit of Radiation Oncology quality care, patient satisfaction, and workforce commitment. To acquire a set of useful measurement tools with which an individual Radiation Oncology practice can benchmark its performance against guidelines defined by accreditation and professional organizations and regulatory agencies.

TH-D-204-01: The Pursuit of Radiation Oncology Performance Excellence

International Nuclear Information System (INIS)

Sternick, E.

2016-01-01

The Malcolm Baldrige National Quality Improvement Act was signed into law in 1987 to advance U.S. business competitiveness and economic growth. Administered by the National Institute of Standards and Technology NIST, the Act created the Baldrige National Quality Program, now renamed the Baldrige Performance Excellence Program. The comprehensive analytical approaches referred to as the Baldrige Healthcare Criteria, are very well suited for the evaluation and sustainable improvement of radiation oncology management and operations. A multidisciplinary self-assessment approach is used for radiotherapy program evaluation and development in order to generate a fact based knowledge driven system for improving quality of care, increasing patient satisfaction, building employee engagement, and boosting organizational innovation. The methodology also provides a valuable framework for benchmarking an individual radiation oncology practice against guidelines defined by accreditation and professional organizations and regulatory agencies. Learning Objectives: To gain knowledge of the Baldrige Performance Excellence Program as it relates to Radiation Oncology. To appreciate the value of a multidisciplinary self-assessment approach in the pursuit of Radiation Oncology quality care, patient satisfaction, and workforce commitment. To acquire a set of useful measurement tools with which an individual Radiation Oncology practice can benchmark its performance against guidelines defined by accreditation and professional organizations and regulatory agencies.

A comparison of random forest regression and multiple linear regression for prediction in neuroscience.

Science.gov (United States)

Smith, Paul F; Ganesh, Siva; Liu, Ping

2013-10-30

Regression is a common statistical tool for prediction in neuroscience. However, linear regression is by far the most common form of regression used, with regression trees receiving comparatively little attention. In this study, the results of conventional multiple linear regression (MLR) were compared with those of random forest regression (RFR), in the prediction of the concentrations of 9 neurochemicals in the vestibular nucleus complex and cerebellum that are part of the l-arginine biochemical pathway (agmatine, putrescine, spermidine, spermine, l-arginine, l-ornithine, l-citrulline, glutamate and γ-aminobutyric acid (GABA)). The R(2) values for the MLRs were higher than the proportion of variance explained values for the RFRs: 6/9 of them were ≥ 0.70 compared to 4/9 for RFRs. Even the variables that had the lowest R(2) values for the MLRs, e.g. ornithine (0.50) and glutamate (0.61), had much lower proportion of variance explained values for the RFRs (0.27 and 0.49, respectively). The RSE values for the MLRs were lower than those for the RFRs in all but two cases. In general, MLRs seemed to be superior to the RFRs in terms of predictive value and error. In the case of this data set, MLR appeared to be superior to RFR in terms of its explanatory value and error. This result suggests that MLR may have advantages over RFR for prediction in neuroscience with this kind of data set, but that RFR can still have good predictive value in some cases. Copyright © 2013 Elsevier B.V. All rights reserved.

Linear and nonlinear models for predicting fish bioconcentration factors for pesticides.

Science.gov (United States)

Yuan, Jintao; Xie, Chun; Zhang, Ting; Sun, Jinfang; Yuan, Xuejie; Yu, Shuling; Zhang, Yingbiao; Cao, Yunyuan; Yu, Xingchen; Yang, Xuan; Yao, Wu

2016-08-01

This work is devoted to the applications of the multiple linear regression (MLR), multilayer perceptron neural network (MLP NN) and projection pursuit regression (PPR) to quantitative structure-property relationship analysis of bioconcentration factors (BCFs) of pesticides tested on Bluegill (Lepomis macrochirus). Molecular descriptors of a total of 107 pesticides were calculated with the DRAGON Software and selected by inverse enhanced replacement method. Based on the selected DRAGON descriptors, a linear model was built by MLR, nonlinear models were developed using MLP NN and PPR. The robustness of the obtained models was assessed by cross-validation and external validation using test set. Outliers were also examined and deleted to improve predictive power. Comparative results revealed that PPR achieved the most accurate predictions. This study offers useful models and information for BCF prediction, risk assessment, and pesticide formulation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Logistic regression applied to natural hazards: rare event logistic regression with replications

OpenAIRE

Guns, M.; Vanacker, Veerle

2012-01-01

Statistical analysis of natural hazards needs particular attention, as most of these phenomena are rare events. This study shows that the ordinary rare event logistic regression, as it is now commonly used in geomorphologic studies, does not always lead to a robust detection of controlling factors, as the results can be strongly sample-dependent. In this paper, we introduce some concepts of Monte Carlo simulations in rare event logistic regression. This technique, so-called rare event logisti...

A Seemingly Unrelated Poisson Regression Model

OpenAIRE

King, Gary

1989-01-01

This article introduces a new estimator for the analysis of two contemporaneously correlated endogenous event count variables. This seemingly unrelated Poisson regression model (SUPREME) estimator combines the efficiencies created by single equation Poisson regression model estimators and insights from "seemingly unrelated" linear regression models.

Recursive Algorithm For Linear Regression

Science.gov (United States)

Varanasi, S. V.

1988-01-01

Order of model determined easily. Linear-regression algorithhm includes recursive equations for coefficients of model of increased order. Algorithm eliminates duplicative calculations, facilitates search for minimum order of linear-regression model fitting set of data satisfactory.

Applied regression analysis a research tool

CERN Document Server

Pantula, Sastry; Dickey, David

1998-01-01

Least squares estimation, when used appropriately, is a powerful research tool. A deeper understanding of the regression concepts is essential for achieving optimal benefits from a least squares analysis. This book builds on the fundamentals of statistical methods and provides appropriate concepts that will allow a scientist to use least squares as an effective research tool. Applied Regression Analysis is aimed at the scientist who wishes to gain a working knowledge of regression analysis. The basic purpose of this book is to develop an understanding of least squares and related statistical methods without becoming excessively mathematical. It is the outgrowth of more than 30 years of consulting experience with scientists and many years of teaching an applied regression course to graduate students. Applied Regression Analysis serves as an excellent text for a service course on regression for non-statisticians and as a reference for researchers. It also provides a bridge between a two-semester introduction to...

Sparsely corrupted stimulated scattering signals recovery by iterative reweighted continuous basis pursuit

Energy Technology Data Exchange (ETDEWEB)

Wang, Kunpeng; Chai, Yi [College of Automation, Chongqing University, Chongqing 400044 (China); Su, Chunxiao [Research Center of Laser Fusion, CAEP, P. O. Box 919-983, Mianyang 621900 (China)

2013-08-15

In this paper, we consider the problem of extracting the desired signals from noisy measurements. This is a classical problem of signal recovery which is of paramount importance in inertial confinement fusion. To accomplish this task, we develop a tractable algorithm based on continuous basis pursuit and reweighted ℓ{sub 1}-minimization. By modeling the observed signals as superposition of scale time-shifted copies of theoretical waveform, structured noise, and unstructured noise on a finite time interval, a sparse optimization problem is obtained. We propose to solve this problem through an iterative procedure that alternates between convex optimization to estimate the amplitude, and local optimization to estimate the dictionary. The performance of the method was evaluated both numerically and experimentally. Numerically, we recovered theoretical signals embedded in increasing amounts of unstructured noise and compared the results with those obtained through popular denoising methods. We also applied the proposed method to a set of actual experimental data acquired from the Shenguang-II laser whose energy was below the detector noise-equivalent energy. Both simulation and experiments show that the proposed method improves the signal recovery performance and extends the dynamic detection range of detectors.

Sparsely corrupted stimulated scattering signals recovery by iterative reweighted continuous basis pursuit

International Nuclear Information System (INIS)

Wang, Kunpeng; Chai, Yi; Su, Chunxiao

2013-01-01

In this paper, we consider the problem of extracting the desired signals from noisy measurements. This is a classical problem of signal recovery which is of paramount importance in inertial confinement fusion. To accomplish this task, we develop a tractable algorithm based on continuous basis pursuit and reweighted ℓ 1 -minimization. By modeling the observed signals as superposition of scale time-shifted copies of theoretical waveform, structured noise, and unstructured noise on a finite time interval, a sparse optimization problem is obtained. We propose to solve this problem through an iterative procedure that alternates between convex optimization to estimate the amplitude, and local optimization to estimate the dictionary. The performance of the method was evaluated both numerically and experimentally. Numerically, we recovered theoretical signals embedded in increasing amounts of unstructured noise and compared the results with those obtained through popular denoising methods. We also applied the proposed method to a set of actual experimental data acquired from the Shenguang-II laser whose energy was below the detector noise-equivalent energy. Both simulation and experiments show that the proposed method improves the signal recovery performance and extends the dynamic detection range of detectors

RMP: Reduced-set matching pursuit approach for efficient compressed sensing signal reconstruction

Directory of Open Access Journals (Sweden)

Michael M. Abdel-Sayed

2016-11-01

Full Text Available Compressed sensing enables the acquisition of sparse signals at a rate that is much lower than the Nyquist rate. Compressed sensing initially adopted ℓ1 minimization for signal reconstruction which is computationally expensive. Several greedy recovery algorithms have been recently proposed for signal reconstruction at a lower computational complexity compared to the optimal ℓ1 minimization, while maintaining a good reconstruction accuracy. In this paper, the Reduced-set Matching Pursuit (RMP greedy recovery algorithm is proposed for compressed sensing. Unlike existing approaches which either select too many or too few values per iteration, RMP aims at selecting the most sufficient number of correlation values per iteration, which improves both the reconstruction time and error. Furthermore, RMP prunes the estimated signal, and hence, excludes the incorrectly selected values. The RMP algorithm achieves a higher reconstruction accuracy at a significantly low computational complexity compared to existing greedy recovery algorithms. It is even superior to ℓ1 minimization in terms of the normalized time-error product, a new metric introduced to measure the trade-off between the reconstruction time and error. RMP superior performance is illustrated with both noiseless and noisy samples.

RMP: Reduced-set matching pursuit approach for efficient compressed sensing signal reconstruction.

Science.gov (United States)

Abdel-Sayed, Michael M; Khattab, Ahmed; Abu-Elyazeed, Mohamed F

2016-11-01

Compressed sensing enables the acquisition of sparse signals at a rate that is much lower than the Nyquist rate. Compressed sensing initially adopted [Formula: see text] minimization for signal reconstruction which is computationally expensive. Several greedy recovery algorithms have been recently proposed for signal reconstruction at a lower computational complexity compared to the optimal [Formula: see text] minimization, while maintaining a good reconstruction accuracy. In this paper, the Reduced-set Matching Pursuit (RMP) greedy recovery algorithm is proposed for compressed sensing. Unlike existing approaches which either select too many or too few values per iteration, RMP aims at selecting the most sufficient number of correlation values per iteration, which improves both the reconstruction time and error. Furthermore, RMP prunes the estimated signal, and hence, excludes the incorrectly selected values. The RMP algorithm achieves a higher reconstruction accuracy at a significantly low computational complexity compared to existing greedy recovery algorithms. It is even superior to [Formula: see text] minimization in terms of the normalized time-error product, a new metric introduced to measure the trade-off between the reconstruction time and error. RMP superior performance is illustrated with both noiseless and noisy samples.

Regression-Based Norms for a Bi-factor Model for Scoring the Brief Test of Adult Cognition by Telephone (BTACT).

Science.gov (United States)

Gurnani, Ashita S; John, Samantha E; Gavett, Brandon E

2015-05-01

The current study developed regression-based normative adjustments for a bi-factor model of the The Brief Test of Adult Cognition by Telephone (BTACT). Archival data from the Midlife Development in the United States-II Cognitive Project were used to develop eight separate linear regression models that predicted bi-factor BTACT scores, accounting for age, education, gender, and occupation-alone and in various combinations. All regression models provided statistically significant fit to the data. A three-predictor regression model fit best and accounted for 32.8% of the variance in the global bi-factor BTACT score. The fit of the regression models was not improved by gender. Eight different regression models are presented to allow the user flexibility in applying demographic corrections to the bi-factor BTACT scores. Occupation corrections, while not widely used, may provide useful demographic adjustments for adult populations or for those individuals who have attained an occupational status not commensurate with expected educational attainment. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The Pursuit of Quantum Gravity Memoirs of Bryce DeWitt from 1946 to 2004

CERN Document Server

DeWitt-Morette, Cécile

2011-01-01

1946 is the year Bryce DeWitt entered Harvard graduate school. Quantum Gravity was his goal and remained his goal throughout his lifetime until the very end. The pursuit of Quantum Gravity requires a profound understanding of Quantum Physics and Gravitation Physics. As G. A. Vilkovisky commented , "Quantum Gravity is a combination of two words, and one should know both. Bryce understood this as nobody else, and this wisdom is completely unknown to many authors of the flux of papers that we see nowadays." Distingished physicist Cecile DeWitt-Morette skillfully blends her personal and scientific account with a wealth of her late husband's often unpublished writings on the subject matter. This volume, through the perspective of the leading researcher on quantum gravity of his generation, will provide an invaluable source of reference for anyone working in the field. "I found the book both instructive and fascinating. Bryce DeWitt and Cécile DeWitt-Morette formed the most creative couple in physics that I have e...

On the Choice of Difference Sequence in a Unified Framework for Variance Estimation in Nonparametric Regression

KAUST Repository

Dai, Wenlin; Tong, Tiejun; Zhu, Lixing

2017-01-01

Difference-based methods do not require estimating the mean function in nonparametric regression and are therefore popular in practice. In this paper, we propose a unified framework for variance estimation that combines the linear regression method with the higher-order difference estimators systematically. The unified framework has greatly enriched the existing literature on variance estimation that includes most existing estimators as special cases. More importantly, the unified framework has also provided a smart way to solve the challenging difference sequence selection problem that remains a long-standing controversial issue in nonparametric regression for several decades. Using both theory and simulations, we recommend to use the ordinary difference sequence in the unified framework, no matter if the sample size is small or if the signal-to-noise ratio is large. Finally, to cater for the demands of the application, we have developed a unified R package, named VarED, that integrates the existing difference-based estimators and the unified estimators in nonparametric regression and have made it freely available in the R statistical program http://cran.r-project.org/web/packages/.

On the Choice of Difference Sequence in a Unified Framework for Variance Estimation in Nonparametric Regression

KAUST Repository

Dai, Wenlin

2017-09-01

Difference-based methods do not require estimating the mean function in nonparametric regression and are therefore popular in practice. In this paper, we propose a unified framework for variance estimation that combines the linear regression method with the higher-order difference estimators systematically. The unified framework has greatly enriched the existing literature on variance estimation that includes most existing estimators as special cases. More importantly, the unified framework has also provided a smart way to solve the challenging difference sequence selection problem that remains a long-standing controversial issue in nonparametric regression for several decades. Using both theory and simulations, we recommend to use the ordinary difference sequence in the unified framework, no matter if the sample size is small or if the signal-to-noise ratio is large. Finally, to cater for the demands of the application, we have developed a unified R package, named VarED, that integrates the existing difference-based estimators and the unified estimators in nonparametric regression and have made it freely available in the R statistical program http://cran.r-project.org/web/packages/.

Standards for Standardized Logistic Regression Coefficients

Science.gov (United States)

Menard, Scott

2011-01-01

Standardized coefficients in logistic regression analysis have the same utility as standardized coefficients in linear regression analysis. Although there has been no consensus on the best way to construct standardized logistic regression coefficients, there is now sufficient evidence to suggest a single best approach to the construction of a…

[Application of negative binomial regression and modified Poisson regression in the research of risk factors for injury frequency].

Science.gov (United States)

Cao, Qingqing; Wu, Zhenqiang; Sun, Ying; Wang, Tiezhu; Han, Tengwei; Gu, Chaomei; Sun, Yehuan

2011-11-01

To Eexplore the application of negative binomial regression and modified Poisson regression analysis in analyzing the influential factors for injury frequency and the risk factors leading to the increase of injury frequency. 2917 primary and secondary school students were selected from Hefei by cluster random sampling method and surveyed by questionnaire. The data on the count event-based injuries used to fitted modified Poisson regression and negative binomial regression model. The risk factors incurring the increase of unintentional injury frequency for juvenile students was explored, so as to probe the efficiency of these two models in studying the influential factors for injury frequency. The Poisson model existed over-dispersion (P Poisson regression and negative binomial regression model, was fitted better. respectively. Both showed that male gender, younger age, father working outside of the hometown, the level of the guardian being above junior high school and smoking might be the results of higher injury frequencies. On a tendency of clustered frequency data on injury event, both the modified Poisson regression analysis and negative binomial regression analysis can be used. However, based on our data, the modified Poisson regression fitted better and this model could give a more accurate interpretation of relevant factors affecting the frequency of injury.

Logistic regression for dichotomized counts.

Science.gov (United States)

Preisser, John S; Das, Kalyan; Benecha, Habtamu; Stamm, John W

2016-12-01

Sometimes there is interest in a dichotomized outcome indicating whether a count variable is positive or zero. Under this scenario, the application of ordinary logistic regression may result in efficiency loss, which is quantifiable under an assumed model for the counts. In such situations, a shared-parameter hurdle model is investigated for more efficient estimation of regression parameters relating to overall effects of covariates on the dichotomous outcome, while handling count data with many zeroes. One model part provides a logistic regression containing marginal log odds ratio effects of primary interest, while an ancillary model part describes the mean count of a Poisson or negative binomial process in terms of nuisance regression parameters. Asymptotic efficiency of the logistic model parameter estimators of the two-part models is evaluated with respect to ordinary logistic regression. Simulations are used to assess the properties of the models with respect to power and Type I error, the latter investigated under both misspecified and correctly specified models. The methods are applied to data from a randomized clinical trial of three toothpaste formulations to prevent incident dental caries in a large population of Scottish schoolchildren. © The Author(s) 2014.

Bayesian ARTMAP for regression.

Science.gov (United States)

Sasu, L M; Andonie, R

2013-10-01

Bayesian ARTMAP (BA) is a recently introduced neural architecture which uses a combination of Fuzzy ARTMAP competitive learning and Bayesian learning. Training is generally performed online, in a single-epoch. During training, BA creates input data clusters as Gaussian categories, and also infers the conditional probabilities between input patterns and categories, and between categories and classes. During prediction, BA uses Bayesian posterior probability estimation. So far, BA was used only for classification. The goal of this paper is to analyze the efficiency of BA for regression problems. Our contributions are: (i) we generalize the BA algorithm using the clustering functionality of both ART modules, and name it BA for Regression (BAR); (ii) we prove that BAR is a universal approximator with the best approximation property. In other words, BAR approximates arbitrarily well any continuous function (universal approximation) and, for every given continuous function, there is one in the set of BAR approximators situated at minimum distance (best approximation); (iii) we experimentally compare the online trained BAR with several neural models, on the following standard regression benchmarks: CPU Computer Hardware, Boston Housing, Wisconsin Breast Cancer, and Communities and Crime. Our results show that BAR is an appropriate tool for regression tasks, both for theoretical and practical reasons. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mechanisms of neuroblastoma regression

Science.gov (United States)

Brodeur, Garrett M.; Bagatell, Rochelle

2014-01-01

Recent genomic and biological studies of neuroblastoma have shed light on the dramatic heterogeneity in the clinical behaviour of this disease, which spans from spontaneous regression or differentiation in some patients, to relentless disease progression in others, despite intensive multimodality therapy. This evidence also suggests several possible mechanisms to explain the phenomena of spontaneous regression in neuroblastomas, including neurotrophin deprivation, humoral or cellular immunity, loss of telomerase activity and alterations in epigenetic regulation. A better understanding of the mechanisms of spontaneous regression might help to identify optimal therapeutic approaches for patients with these tumours. Currently, the most druggable mechanism is the delayed activation of developmentally programmed cell death regulated by the tropomyosin receptor kinase A pathway. Indeed, targeted therapy aimed at inhibiting neurotrophin receptors might be used in lieu of conventional chemotherapy or radiation in infants with biologically favourable tumours that require treatment. Alternative approaches consist of breaking immune tolerance to tumour antigens or activating neurotrophin receptor pathways to induce neuronal differentiation. These approaches are likely to be most effective against biologically favourable tumours, but they might also provide insights into treatment of biologically unfavourable tumours. We describe the different mechanisms of spontaneous neuroblastoma regression and the consequent therapeutic approaches. PMID:25331179

Using the Ridge Regression Procedures to Estimate the Multiple Linear Regression Coefficients

Science.gov (United States)

Gorgees, HazimMansoor; Mahdi, FatimahAssim

2018-05-01

This article concerns with comparing the performance of different types of ordinary ridge regression estimators that have been already proposed to estimate the regression parameters when the near exact linear relationships among the explanatory variables is presented. For this situations we employ the data obtained from tagi gas filling company during the period (2008-2010). The main result we reached is that the method based on the condition number performs better than other methods since it has smaller mean square error (MSE) than the other stated methods.

Multicollinearity and Regression Analysis

Science.gov (United States)

Daoud, Jamal I.

2017-12-01

In regression analysis it is obvious to have a correlation between the response and predictor(s), but having correlation among predictors is something undesired. The number of predictors included in the regression model depends on many factors among which, historical data, experience, etc. At the end selection of most important predictors is something objective due to the researcher. Multicollinearity is a phenomena when two or more predictors are correlated, if this happens, the standard error of the coefficients will increase [8]. Increased standard errors means that the coefficients for some or all independent variables may be found to be significantly different from In other words, by overinflating the standard errors, multicollinearity makes some variables statistically insignificant when they should be significant. In this paper we focus on the multicollinearity, reasons and consequences on the reliability of the regression model.

Panel Smooth Transition Regression Models

DEFF Research Database (Denmark)

González, Andrés; Terasvirta, Timo; Dijk, Dick van

We introduce the panel smooth transition regression model. This new model is intended for characterizing heterogeneous panels, allowing the regression coefficients to vary both across individuals and over time. Specifically, heterogeneity is allowed for by assuming that these coefficients are bou...

Kepler AutoRegressive Planet Search (KARPS)

Science.gov (United States)

Caceres, Gabriel

2018-01-01

One of the main obstacles in detecting faint planetary transits is the intrinsic stellar variability of the host star. The Kepler AutoRegressive Planet Search (KARPS) project implements statistical methodology associated with autoregressive processes (in particular, ARIMA and ARFIMA) to model stellar lightcurves in order to improve exoplanet transit detection. We also develop a novel Transit Comb Filter (TCF) applied to the AR residuals which provides a periodogram analogous to the standard Box-fitting Least Squares (BLS) periodogram. We train a random forest classifier on known Kepler Objects of Interest (KOIs) using select features from different stages of this analysis, and then use ROC curves to define and calibrate the criteria to recover the KOI planet candidates with high fidelity. These statistical methods are detailed in a contributed poster (Feigelson et al., this meeting).These procedures are applied to the full DR25 dataset of NASA’s Kepler mission. Using the classification criteria, a vast majority of known KOIs are recovered and dozens of new KARPS Candidate Planets (KCPs) discovered, including ultra-short period exoplanets. The KCPs will be briefly presented and discussed.

Credit Scoring Problem Based on Regression Analysis

OpenAIRE

Khassawneh, Bashar Suhil Jad Allah

2014-01-01

ABSTRACT: This thesis provides an explanatory introduction to the regression models of data mining and contains basic definitions of key terms in the linear, multiple and logistic regression models. Meanwhile, the aim of this study is to illustrate fitting models for the credit scoring problem using simple linear, multiple linear and logistic regression models and also to analyze the found model functions by statistical tools. Keywords: Data mining, linear regression, logistic regression....

Untrivial Pursuit: Measuring Motor Procedures Learning in Children with Autism.

Science.gov (United States)

Sparaci, Laura; Formica, Domenico; Lasorsa, Francesca Romana; Mazzone, Luigi; Valeri, Giovanni; Vicari, Stefano

2015-08-01

Numerous studies have underscored prevalence of motor impairments in children with autism spectrum disorders (ASD), but only few of them have analyzed motor strategies exploited by ASD children when learning a new motor procedure. To evaluate motor procedure learning and performance strategies in both ASD and typically developing (TD) children, we built a virtual pursuit rotor (VPR) task, requiring tracking a moving target on a computer screen using a digitalized pen and tablet. Procedural learning was measured as increased time on target (TT) across blocks of trials on the same day and consolidation was assessed after a 24-hour rest. The program and the experimental setting (evaluated in a first experiment considering two groups of TD children) allowed also measures of continuous time on target (CTT), distance from target (DT) and distance from path (DP), as well as 2D reconstructions of children's trajectories. Results showed that the VPR was harder for children with ASD than for TD controls matched for chronological age and intelligence quotient, but both groups displayed comparable motor procedure learning (i.e., similarly incremented their TT). However, closer analysis of CTT, DT, and DP as well as 2D trajectories, showed different motor performance strategies in ASD, highlighting difficulties in overall actions planning. Data underscore the need for deeper investigations of motor strategies exploited by children with ASD when learning a new motor procedure. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

Unbalanced Regressions and the Predictive Equation

DEFF Research Database (Denmark)

Osterrieder, Daniela; Ventosa-Santaulària, Daniel; Vera-Valdés, J. Eduardo

Predictive return regressions with persistent regressors are typically plagued by (asymptotically) biased/inconsistent estimates of the slope, non-standard or potentially even spurious statistical inference, and regression unbalancedness. We alleviate the problem of unbalancedness in the theoreti......Predictive return regressions with persistent regressors are typically plagued by (asymptotically) biased/inconsistent estimates of the slope, non-standard or potentially even spurious statistical inference, and regression unbalancedness. We alleviate the problem of unbalancedness...... in the theoretical predictive equation by suggesting a data generating process, where returns are generated as linear functions of a lagged latent I(0) risk process. The observed predictor is a function of this latent I(0) process, but it is corrupted by a fractionally integrated noise. Such a process may arise due...... to aggregation or unexpected level shifts. In this setup, the practitioner estimates a misspecified, unbalanced, and endogenous predictive regression. We show that the OLS estimate of this regression is inconsistent, but standard inference is possible. To obtain a consistent slope estimate, we then suggest...

[From clinical judgment to linear regression model.

Science.gov (United States)

Palacios-Cruz, Lino; Pérez, Marcela; Rivas-Ruiz, Rodolfo; Talavera, Juan O

2013-01-01

When we think about mathematical models, such as linear regression model, we think that these terms are only used by those engaged in research, a notion that is far from the truth. Legendre described the first mathematical model in 1805, and Galton introduced the formal term in 1886. Linear regression is one of the most commonly used regression models in clinical practice. It is useful to predict or show the relationship between two or more variables as long as the dependent variable is quantitative and has normal distribution. Stated in another way, the regression is used to predict a measure based on the knowledge of at least one other variable. Linear regression has as it's first objective to determine the slope or inclination of the regression line: Y = a + bx, where "a" is the intercept or regression constant and it is equivalent to "Y" value when "X" equals 0 and "b" (also called slope) indicates the increase or decrease that occurs when the variable "x" increases or decreases in one unit. In the regression line, "b" is called regression coefficient. The coefficient of determination (R 2 ) indicates the importance of independent variables in the outcome.

Autistic Regression

Science.gov (United States)

Matson, Johnny L.; Kozlowski, Alison M.

2010-01-01

Autistic regression is one of the many mysteries in the developmental course of autism and pervasive developmental disorders not otherwise specified (PDD-NOS). Various definitions of this phenomenon have been used, further clouding the study of the topic. Despite this problem, some efforts at establishing prevalence have been made. The purpose of…

Ridge regression estimator: combining unbiased and ordinary ridge regression methods of estimation

Directory of Open Access Journals (Sweden)

Sharad Damodar Gore

2009-10-01

Full Text Available Statistical literature has several methods for coping with multicollinearity. This paper introduces a new shrinkage estimator, called modified unbiased ridge (MUR. This estimator is obtained from unbiased ridge regression (URR in the same way that ordinary ridge regression (ORR is obtained from ordinary least squares (OLS. Properties of MUR are derived. Results on its matrix mean squared error (MMSE are obtained. MUR is compared with ORR and URR in terms of MMSE. These results are illustrated with an example based on data generated by Hoerl and Kennard (1975.

An evaluation of the effectiveness of observation camera placement within the MeerKAT radio telescope project

Directory of Open Access Journals (Sweden)

Heyns, Andries

2015-08-01

Full Text Available A recent development within the MeerKAT sub-project of the Square Kilometre Array radio telescope network was the placement of a network of three observation cameras in pursuit of two specific visibility objectives. In this paper, we evaluate the effectiveness of the locations of the MeerKAT observation camera network according to a novel multi-objective geographic information systems-based facility location framework. We find that the configuration chosen and implemented by the MeerKAT decision-makers is of very high quality, although we are able to uncover slightly superior alternative placement configurations. A significant amount of time and effort could, however, have been saved in the process of choosing the appropriate camera sites, had our solutions been available to the decision-makers.

Categorical regression dose-response modeling

Science.gov (United States)

The goal of this training is to provide participants with training on the use of the U.S. EPA’s Categorical Regression soft¬ware (CatReg) and its application to risk assessment. Categorical regression fits mathematical models to toxicity data that have been assigned ord...

Abstract Expression Grammar Symbolic Regression

Science.gov (United States)

Korns, Michael F.

This chapter examines the use of Abstract Expression Grammars to perform the entire Symbolic Regression process without the use of Genetic Programming per se. The techniques explored produce a symbolic regression engine which has absolutely no bloat, which allows total user control of the search space and output formulas, which is faster, and more accurate than the engines produced in our previous papers using Genetic Programming. The genome is an all vector structure with four chromosomes plus additional epigenetic and constraint vectors, allowing total user control of the search space and the final output formulas. A combination of specialized compiler techniques, genetic algorithms, particle swarm, aged layered populations, plus discrete and continuous differential evolution are used to produce an improved symbolic regression sytem. Nine base test cases, from the literature, are used to test the improvement in speed and accuracy. The improved results indicate that these techniques move us a big step closer toward future industrial strength symbolic regression systems.

HUBUNGAN KOMPETENSI PROJECT MANAGER TERHADAP KEBERHASILAN PROYEK KONSTRUKSI GEDUNG

Directory of Open Access Journals (Sweden)

Ida Ayu Ari Brahmantariguna

2016-07-01

Full Text Available Abstract :One of the factor that influences the achievement of a project success is the role of a project manager. A reliable project manager, who knows his duties as a project leader and has the necessary competency requirements is needed to achieve the success of the project. The competence of a project manager can be measured by three aspects: knowledge, skill and attitude.This research  aims to analyze the relationship between project manager competencies (that measured by three independent variables, i.e. Knowledge, skills and attitude and the success of the building construction project. Data was collected through a questionnaire survey. The sample/ respondents were the expertise in the field of building construction services those acts as a project manager. Data was analyzed  in three stages:first, factor analysis to reduce the variables into several groups of factors, that called as independent variables; second, correlation test with Pearson Correlation method to determine the correlation between independent variables  and dependent variable; lastly, perform multivariate regression analysis The results of factor analysis showed that the variables are formed into eleven groups, and the result of Pearson Correlation test showed only six groups correlated to project success, those are: Communication and Scope Management, Human Resource Management, which is part of knowledge; Leadership and Project Management, Professionalism and Issues Management as part of skill; and attitude concerning Responsibility, Vision and Priorities. The sixth group of these factors will be the independent variables in multivariate regression analysis. Based on multiple correlation test results, six independent variables simultaneously have a significant influence to the project success, proved by the result of probability value is 0,032.

Comparison of Classical Linear Regression and Orthogonal Regression According to the Sum of Squares Perpendicular Distances

OpenAIRE

KELEŞ, Taliha; ALTUN, Murat

2016-01-01

Regression analysis is a statistical technique for investigating and modeling the relationship between variables. The purpose of this study was the trivial presentation of the equation for orthogonal regression (OR) and the comparison of classical linear regression (CLR) and OR techniques with respect to the sum of squared perpendicular distances. For that purpose, the analyses were shown by an example. It was found that the sum of squared perpendicular distances of OR is smaller. Thus, it wa...

Pathological assessment of liver fibrosis regression

Directory of Open Access Journals (Sweden)

WANG Bingqiong

2017-03-01

Full Text Available Hepatic fibrosis is the common pathological outcome of chronic hepatic diseases. An accurate assessment of fibrosis degree provides an important reference for a definite diagnosis of diseases, treatment decision-making, treatment outcome monitoring, and prognostic evaluation. At present, many clinical studies have proven that regression of hepatic fibrosis and early-stage liver cirrhosis can be achieved by effective treatment, and a correct evaluation of fibrosis regression has become a hot topic in clinical research. Liver biopsy has long been regarded as the gold standard for the assessment of hepatic fibrosis, and thus it plays an important role in the evaluation of fibrosis regression. This article reviews the clinical application of current pathological staging systems in the evaluation of fibrosis regression from the perspectives of semi-quantitative scoring system, quantitative approach, and qualitative approach, in order to propose a better pathological evaluation system for the assessment of fibrosis regression.

Logistic Regression: Concept and Application

Science.gov (United States)

Cokluk, Omay

2010-01-01

The main focus of logistic regression analysis is classification of individuals in different groups. The aim of the present study is to explain basic concepts and processes of binary logistic regression analysis intended to determine the combination of independent variables which best explain the membership in certain groups called dichotomous…

Predictors of course in obsessive-compulsive disorder: logistic regression versus Cox regression for recurrent events.

Science.gov (United States)

Kempe, P T; van Oppen, P; de Haan, E; Twisk, J W R; Sluis, A; Smit, J H; van Dyck, R; van Balkom, A J L M

2007-09-01

Two methods for predicting remissions in obsessive-compulsive disorder (OCD) treatment are evaluated. Y-BOCS measurements of 88 patients with a primary OCD (DSM-III-R) diagnosis were performed over a 16-week treatment period, and during three follow-ups. Remission at any measurement was defined as a Y-BOCS score lower than thirteen combined with a reduction of seven points when compared with baseline. Logistic regression models were compared with a Cox regression for recurrent events model. Logistic regression yielded different models at different evaluation times. The recurrent events model remained stable when fewer measurements were used. Higher baseline levels of neuroticism and more severe OCD symptoms were associated with a lower chance of remission, early age of onset and more depressive symptoms with a higher chance. Choice of outcome time affects logistic regression prediction models. Recurrent events analysis uses all information on remissions and relapses. Short- and long-term predictors for OCD remission show overlap.

Sparse reduced-rank regression with covariance estimation

KAUST Repository

Chen, Lisha

2014-12-08

Improving the predicting performance of the multiple response regression compared with separate linear regressions is a challenging question. On the one hand, it is desirable to seek model parsimony when facing a large number of parameters. On the other hand, for certain applications it is necessary to take into account the general covariance structure for the errors of the regression model. We assume a reduced-rank regression model and work with the likelihood function with general error covariance to achieve both objectives. In addition we propose to select relevant variables for reduced-rank regression by using a sparsity-inducing penalty, and to estimate the error covariance matrix simultaneously by using a similar penalty on the precision matrix. We develop a numerical algorithm to solve the penalized regression problem. In a simulation study and real data analysis, the new method is compared with two recent methods for multivariate regression and exhibits competitive performance in prediction and variable selection.

Sparse reduced-rank regression with covariance estimation

KAUST Repository

Chen, Lisha; Huang, Jianhua Z.

2014-01-01

Improving the predicting performance of the multiple response regression compared with separate linear regressions is a challenging question. On the one hand, it is desirable to seek model parsimony when facing a large number of parameters. On the other hand, for certain applications it is necessary to take into account the general covariance structure for the errors of the regression model. We assume a reduced-rank regression model and work with the likelihood function with general error covariance to achieve both objectives. In addition we propose to select relevant variables for reduced-rank regression by using a sparsity-inducing penalty, and to estimate the error covariance matrix simultaneously by using a similar penalty on the precision matrix. We develop a numerical algorithm to solve the penalized regression problem. In a simulation study and real data analysis, the new method is compared with two recent methods for multivariate regression and exhibits competitive performance in prediction and variable selection.

Regression models of reactor diagnostic signals

International Nuclear Information System (INIS)

Vavrin, J.

1989-01-01

The application is described of an autoregression model as the simplest regression model of diagnostic signals in experimental analysis of diagnostic systems, in in-service monitoring of normal and anomalous conditions and their diagnostics. The method of diagnostics is described using a regression type diagnostic data base and regression spectral diagnostics. The diagnostics is described of neutron noise signals from anomalous modes in the experimental fuel assembly of a reactor. (author)

Ambidextrous Leadership and Sustainability-Based Project Performance: The Role of Project Culture

Directory of Open Access Journals (Sweden)

Junwei Zheng

2017-12-01

Full Text Available Most studies in the project management field emphasized the effects of leaders or managers, but these effects have rarely been examined at the project level. To cover this research gap, this study applies organizational ambidexterity theory to examine the effects among ambidextrous leadership, ambidextrous culture and sustainability-based project performance. Using a valid sample of 217 project leaders and members from Chinese construction projects, the method of multiple linear regression was adopted to assess the direct relationship among ambidextrous leadership, ambidextrous culture and project performance. Moreover, the bootstrapping technique through structural equation modeling, has been used to analyze the mediating effect of ambidextrous culture. Additionally, the sample data was divided into different groups according to the median value of the variables to conduct the ANOVA and to assess the within-group differences. The results indicated a positive and direct relationship that ambidextrous leadership has on project performance and ambidextrous culture. In addition, there was also a mediating impact of ambidextrous leadership on project performance via ambidextrous culture. Thus, ambidextrous leadership combined with transformational leadership as well as transactional leadership likely has a stronger positive impact on project performance through fostering the adaptive culture and consistent culture. Our findings contribute to an in-depth understanding of the role of the leader and culture for project outcomes. The project-based organization in construction projects could train project leaders’ ambidextrous leadership behavior to facilitate the formation of an ambidextrous culture and to increase project performance. Moreover, this study enriches the existing literature on leadership and project management by highlighting the important path of ambidextrous leadership and ambidextrous culture on the performance at the project level

Regression and Sparse Regression Methods for Viscosity Estimation of Acid Milk From it’s Sls Features

DEFF Research Database (Denmark)

Sharifzadeh, Sara; Skytte, Jacob Lercke; Nielsen, Otto Højager Attermann

2012-01-01

Statistical solutions find wide spread use in food and medicine quality control. We investigate the effect of different regression and sparse regression methods for a viscosity estimation problem using the spectro-temporal features from new Sub-Surface Laser Scattering (SLS) vision system. From...... with sparse LAR, lasso and Elastic Net (EN) sparse regression methods. Due to the inconsistent measurement condition, Locally Weighted Scatter plot Smoothing (Loess) has been employed to alleviate the undesired variation in the estimated viscosity. The experimental results of applying different methods show...

Testing discontinuities in nonparametric regression

KAUST Repository

Dai, Wenlin

2017-01-19

In nonparametric regression, it is often needed to detect whether there are jump discontinuities in the mean function. In this paper, we revisit the difference-based method in [13 H.-G. Müller and U. Stadtmüller, Discontinuous versus smooth regression, Ann. Stat. 27 (1999), pp. 299–337. doi: 10.1214/aos/1018031100

Testing discontinuities in nonparametric regression

KAUST Repository

Dai, Wenlin; Zhou, Yuejin; Tong, Tiejun

2017-01-01

In nonparametric regression, it is often needed to detect whether there are jump discontinuities in the mean function. In this paper, we revisit the difference-based method in [13 H.-G. Müller and U. Stadtmüller, Discontinuous versus smooth regression, Ann. Stat. 27 (1999), pp. 299–337. doi: 10.1214/aos/1018031100

On Solving Lq-Penalized Regressions

Directory of Open Access Journals (Sweden)

Tracy Zhou Wu

2007-01-01

Full Text Available Lq-penalized regression arises in multidimensional statistical modelling where all or part of the regression coefficients are penalized to achieve both accuracy and parsimony of statistical models. There is often substantial computational difficulty except for the quadratic penalty case. The difficulty is partly due to the nonsmoothness of the objective function inherited from the use of the absolute value. We propose a new solution method for the general Lq-penalized regression problem based on space transformation and thus efficient optimization algorithms. The new method has immediate applications in statistics, notably in penalized spline smoothing problems. In particular, the LASSO problem is shown to be polynomial time solvable. Numerical studies show promise of our approach.

Coal Calorific Value Prediction Based on Projection Pursuit Principle

OpenAIRE

QI Minfang; FU Zhongguang; JING Yuan

2012-01-01

The calorific value of coal is an important factor for the economic operation of coal-fired power plant. However, calorific value is tremendous difference between the different coal, and even if coal is from the same mine. Restricted by the coal market, most of coal fired power plants can not burn the designed-coal by now in China. The properties of coal as received are changing so frequently that pulverized coal firing is always with the unexpected condition. Therefore, the researches on the...

Pursuit of communal values in an agentic manner: a way to happiness?

Science.gov (United States)

Abele, Andrea E.

2014-01-01

The present research studies the association between traits, values, and life satisfaction. While values should influence the direction of an individual’s goals and behavior, his/her traits impact effort-expenditure, efficiency, and persistence in goal-pursuit. We apply the framework of the “Big Two” of agency and communion (Bakan, 1966) for distinguishing the content of values and traits. While agentic content refers to qualities relevant for goal-attainment, such as assertiveness, competence or persistence, communal content refers to qualities relevant for the establishment and maintenance of social relationships, such as being friendly, helpful, or fair. We predict that high scores on communal values and high scores on agentic traits are associated with life satisfaction. We test these predictions in two studies conducted in different countries (Germany and Russia) with different cultural background. The findings support our reasoning: across both countries we find positive associations of communal values and agentic traits with life satisfaction; and individuals high in communal values and high in agentic traits are most satisfied with their lives. In Russia, the association of communal values with life satisfaction is moderated by agentic traits; in Germany, however, there is a main effect of communal values. PMID:25477843

A pursuit of significance of the coarsened gastric rugae in radiologic examination

Energy Technology Data Exchange (ETDEWEB)

Kim, Ok Dong [Chung Ang University College of Medicine, Seoul (Korea, Republic of)

1979-06-15

The radiologic upper G.I. series and gastroscopic examination with gastric biopsies of 230 cases were carried out in Korea General Hospital for the purpose of pursuit of significance of coarsened gastric rugae. Out of the above series the 26 cases showing mere radiologic finding of coarsening of the gastric mucosal rugae were selected, excluding the cases with definite evidence of ulceration, malignancies and others. The correlativity of the coarsened gastric rugae was investigated with clinical pictures, gastroscopic features and biopsy findings. The following results were obtained: 1. There were 24 cases of gastritis, 5 of stomach ulcer and 2 of stomach cancer in the 26 cases with mere finding of mucosal coarsening. 2. There was 5 cases of stomach ulcer disease revealing no radiologic evidence, but there were found tiny ulcers in 4 cases and a large ulcer crater of 1.0 cm by 1.5 cm in diameter in the other case under the gastroscopic study. 3. Two cases of stomach cancer were not detected in neither radiologic nor gastroscopic examination, however, they were found by gastric biopsy. 4. It should be strongly emphasized that the biopsy under the gastroscopic control must be followed when a radiologic evidence of coarsened gastric rugae is demonstrated.

Identification of Non-Stationary Magnetic Field Sources Using the Matching Pursuit Method

Directory of Open Access Journals (Sweden)

Beata Palczynska

2017-05-01

Full Text Available The measurements of electromagnetic field emissions, performed on board a vessel have showed that, in this specific environment, a high level of non-stationary magnetic fields (MFs is observed. The adaptive time-frequency method can be used successfully to analyze this type of measured signal. It allows one to specify the time interval in which the individual frequency components of the signal occur. In this paper, the method of identification of non-stationary MF sources based on the matching pursuit (MP algorithm is presented. It consists of the decomposition of an examined time-waveform into the linear expansion of chirplet atoms and the analysis of the matrix of their parameters. The main feature of the proposed method is the modification of the chirplet’s matrix in a way that atoms, whose normalized energies are lower than a certain threshold, will be rejected. On the time-frequency planes of the spectrograms, obtained separately for each remaining chirlpet, it can clearly identify the time-frequency structures appearing in the examined signal. The choice of a threshold defines the computing speed and precision of the performed analysis. The method was implemented in the virtual application and used for processing real data, obtained from measurements of time-vary MF emissions onboard a ship.

Pursuit of communal values in an agentic manner: A way to happiness?

Directory of Open Access Journals (Sweden)

Andrea Elisabeth Abele

2014-11-01

Full Text Available The present research studies the association between traits, values and life satisfaction. While values should influence the direction of an individual’s goals and behaviour, his/her traits impact effort expenditure, efficiency and persistence in goal-pursuit. We apply the framework of the Big Two of agency and communion (Bakan, 1966 for distinguishing the content of values and traits. While agentic content refers to qualities relevant for goal-attainment, such as assertiveness, competence or persistence, communal content refers to qualities relevant for the establishment and maintenance of social relationships, such as being friendly, helpful, or fair. We predict that high scores on communal values and high scores on agentic traits are associated with life satisfaction. We test these predictions in two studies conducted in different countries (Germany and Russia with different cultural background. The findings support our reasoning: Across both countries we find positive associations of communal values and agentic traits with life satisfaction; and individuals high in communal values and high in agentic traits are most satisfied with their lives. In Russia, the association of communal values with life satisfaction is moderated by agentic traits; in Germany, however, there is a main effect of communal values.

A pursuit of significance of the coarsened gastric rugae in radiologic examination

International Nuclear Information System (INIS)

Kim, Ok Dong

1979-01-01

The radiologic upper G.I. series and gastroscopic examination with gastric biopsies of 230 cases were carried out in Korea General Hospital for the purpose of pursuit of significance of coarsened gastric rugae. Out of the above series the 26 cases showing mere radiologic finding of coarsening of the gastric mucosal rugae were selected, excluding the cases with definite evidence of ulceration, malignancies and others. The correlativity of the coarsened gastric rugae was investigated with clinical pictures, gastroscopic features and biopsy findings. The following results were obtained: 1. There were 24 cases of gastritis, 5 of stomach ulcer and 2 of stomach cancer in the 26 cases with mere finding of mucosal coarsening. 2. There was 5 cases of stomach ulcer disease revealing no radiologic evidence, but there were found tiny ulcers in 4 cases and a large ulcer crater of 1.0 cm by 1.5 cm in diameter in the other case under the gastroscopic study. 3. Two cases of stomach cancer were not detected in neither radiologic nor gastroscopic examination, however, they were found by gastric biopsy. 4. It should be strongly emphasized that the biopsy under the gastroscopic control must be followed when a radiologic evidence of coarsened gastric rugae is demonstrated.

Boosted regression trees, multivariate adaptive regression splines and their two-step combinations with multiple linear regression or partial least squares to predict blood-brain barrier passage: a case study.

Science.gov (United States)

Deconinck, E; Zhang, M H; Petitet, F; Dubus, E; Ijjaali, I; Coomans, D; Vander Heyden, Y

2008-02-18

The use of some unconventional non-linear modeling techniques, i.e. classification and regression trees and multivariate adaptive regression splines-based methods, was explored to model the blood-brain barrier (BBB) passage of drugs and drug-like molecules. The data set contains BBB passage values for 299 structural and pharmacological diverse drugs, originating from a structured knowledge-based database. Models were built using boosted regression trees (BRT) and multivariate adaptive regression splines (MARS), as well as their respective combinations with stepwise multiple linear regression (MLR) and partial least squares (PLS) regression in two-step approaches. The best models were obtained using combinations of MARS with either stepwise MLR or PLS. It could be concluded that the use of combinations of a linear with a non-linear modeling technique results in some improved properties compared to the individual linear and non-linear models and that, when the use of such a combination is appropriate, combinations using MARS as non-linear technique should be preferred over those with BRT, due to some serious drawbacks of the BRT approaches.

Testing Heteroscedasticity in Robust Regression

Czech Academy of Sciences Publication Activity Database

Kalina, Jan

2011-01-01

Roč. 1, č. 4 (2011), s. 25-28 ISSN 2045-3345 Grant - others:GA ČR(CZ) GA402/09/0557 Institutional research plan: CEZ:AV0Z10300504 Keywords : robust regression * heteroscedasticity * regression quantiles * diagnostics Subject RIV: BB - Applied Statistics , Operational Research http://www.researchjournals.co.uk/documents/Vol4/06%20Kalina.pdf

Spontaneous regression of a congenital melanocytic nevus

Directory of Open Access Journals (Sweden)

Amiya Kumar Nath

2011-01-01

Full Text Available Congenital melanocytic nevus (CMN may rarely regress which may also be associated with a halo or vitiligo. We describe a 10-year-old girl who presented with CMN on the left leg since birth, which recently started to regress spontaneously with associated depigmentation in the lesion and at a distant site. Dermoscopy performed at different sites of the regressing lesion demonstrated loss of epidermal pigments first followed by loss of dermal pigments. Histopathology and Masson-Fontana stain demonstrated lymphocytic infiltration and loss of pigment production in the regressing area. Immunohistochemistry staining (S100 and HMB-45, however, showed that nevus cells were present in the regressing areas.

Structuring the collaboration of science and service in pursuit of a shared vision.

Science.gov (United States)

Chorpita, Bruce F; Daleiden, Eric L

2014-01-01

The enduring needs of our society highlight the importance of a shared vision to improve human functioning and yield better lives for families and communities. Science offers a powerful strategy for managing the inevitable uncertainty in pursuit of these goals. This article presents ideas and examples of methods that could preserve the strengths of the two major paradigms in children's mental health, evidence-based treatments and individualized care models, but that also have the potential to extend their applicability and impact. As exemplified in some of the articles throughout this issue, new models to connect science and service will likely emerge from novel consideration of better ways to structure and inform collaboration within mental health systems. We contend that the future models for effective systems will involve increased attention to (a) client and provider developmental pathways, (b) explicit frameworks for coordinating people and the knowledge and other resources they use, and (c) a balance of evidence-based planning and informed adaptation. We encourage the diverse community of scientists, providers, and administrators in our field to come together to enhance our collective wisdom through consideration of and reflection on these concepts and their illustrations.

Sparse and Dispersion-Based Matching Pursuit for Minimizing the Dispersion Effect Occurring when Using Guided Wave for Pipe Inspection.

Science.gov (United States)

Rostami, Javad; Tse, Peter W T; Fang, Zhou

2017-06-06

Ultrasonic guided wave is an effective tool for structural health monitoring of structures for detecting defects. In practice, guided wave signals are dispersive and contain multiple modes and noise. In the presence of overlapped wave-packets/modes and noise together with dispersion, extracting meaningful information from these signals is a challenging task. Handling such challenge requires an advanced signal processing tool. The aim of this study is to develop an effective and robust signal processing tool to deal with the complexity of guided wave signals for non-destructive testing (NDT) purpose. To achieve this goal, Sparse Representation with Dispersion Based Matching Pursuit (SDMP) is proposed. Addressing the three abovementioned facts that complicate signal interpretation, SDMP separates overlapped modes and demonstrates good performance against noise with maximum sparsity. With the dispersion taken into account, an overc-omplete and redundant dictionary of basic atoms based on a narrowband excitation signal is designed. As Finite Element Method (FEM) was used to predict the form of wave packets propagating along structures, these atoms have the maximum resemblance with real guided wave signals. SDMP operates in two stages. In the first stage, similar to Matching Pursuit (MP), the approximation improves by adding, a single atom to the solution set at each iteration. However, atom selection criterion of SDMP utilizes the time localization of guided wave reflections that makes a portion of overlapped wave-packets to be composed mainly of a single echo. In the second stage of the algorithm, the selected atoms that have frequency inconsistency with the excitation signal are discarded. This increases the sparsity of the final representation. Meanwhile, leading to accurate approximation, as discarded atoms are not representing guided wave reflections, it simplifies extracting physical meanings for defect detection purpose. To verify the effectiveness of SDMP for

Sparse and Dispersion-Based Matching Pursuit for Minimizing the Dispersion Effect Occurring when Using Guided Wave for Pipe Inspection

Directory of Open Access Journals (Sweden)

Javad Rostami

2017-06-01

Full Text Available Ultrasonic guided wave is an effective tool for structural health monitoring of structures for detecting defects. In practice, guided wave signals are dispersive and contain multiple modes and noise. In the presence of overlapped wave-packets/modes and noise together with dispersion, extracting meaningful information from these signals is a challenging task. Handling such challenge requires an advanced signal processing tool. The aim of this study is to develop an effective and robust signal processing tool to deal with the complexity of guided wave signals for non-destructive testing (NDT purpose. To achieve this goal, Sparse Representation with Dispersion Based Matching Pursuit (SDMP is proposed. Addressing the three abovementioned facts that complicate signal interpretation, SDMP separates overlapped modes and demonstrates good performance against noise with maximum sparsity. With the dispersion taken into account, an overc-omplete and redundant dictionary of basic atoms based on a narrowband excitation signal is designed. As Finite Element Method (FEM was used to predict the form of wave packets propagating along structures, these atoms have the maximum resemblance with real guided wave signals. SDMP operates in two stages. In the first stage, similar to Matching Pursuit (MP, the approximation improves by adding, a single atom to the solution set at each iteration. However, atom selection criterion of SDMP utilizes the time localization of guided wave reflections that makes a portion of overlapped wave-packets to be composed mainly of a single echo. In the second stage of the algorithm, the selected atoms that have frequency inconsistency with the excitation signal are discarded. This increases the sparsity of the final representation. Meanwhile, leading to accurate approximation, as discarded atoms are not representing guided wave reflections, it simplifies extracting physical meanings for defect detection purpose. To verify the

Regression Analysis by Example. 5th Edition

Science.gov (United States)

Chatterjee, Samprit; Hadi, Ali S.

2012-01-01

Regression analysis is a conceptually simple method for investigating relationships among variables. Carrying out a successful application of regression analysis, however, requires a balance of theoretical results, empirical rules, and subjective judgment. "Regression Analysis by Example, Fifth Edition" has been expanded and thoroughly…

Gaussian process regression analysis for functional data

CERN Document Server

Shi, Jian Qing

2011-01-01

Gaussian Process Regression Analysis for Functional Data presents nonparametric statistical methods for functional regression analysis, specifically the methods based on a Gaussian process prior in a functional space. The authors focus on problems involving functional response variables and mixed covariates of functional and scalar variables.Covering the basics of Gaussian process regression, the first several chapters discuss functional data analysis, theoretical aspects based on the asymptotic properties of Gaussian process regression models, and new methodological developments for high dime

Is past life regression therapy ethical?

Science.gov (United States)

Andrade, Gabriel

2017-01-01

Past life regression therapy is used by some physicians in cases with some mental diseases. Anxiety disorders, mood disorders, and gender dysphoria have all been treated using life regression therapy by some doctors on the assumption that they reflect problems in past lives. Although it is not supported by psychiatric associations, few medical associations have actually condemned it as unethical. In this article, I argue that past life regression therapy is unethical for two basic reasons. First, it is not evidence-based. Past life regression is based on the reincarnation hypothesis, but this hypothesis is not supported by evidence, and in fact, it faces some insurmountable conceptual problems. If patients are not fully informed about these problems, they cannot provide an informed consent, and hence, the principle of autonomy is violated. Second, past life regression therapy has the great risk of implanting false memories in patients, and thus, causing significant harm. This is a violation of the principle of non-malfeasance, which is surely the most important principle in medical ethics.

Regression Models for Market-Shares

DEFF Research Database (Denmark)

Birch, Kristina; Olsen, Jørgen Kai; Tjur, Tue

2005-01-01

On the background of a data set of weekly sales and prices for three brands of coffee, this paper discusses various regression models and their relation to the multiplicative competitive-interaction model (the MCI model, see Cooper 1988, 1993) for market-shares. Emphasis is put on the interpretat......On the background of a data set of weekly sales and prices for three brands of coffee, this paper discusses various regression models and their relation to the multiplicative competitive-interaction model (the MCI model, see Cooper 1988, 1993) for market-shares. Emphasis is put...... on the interpretation of the parameters in relation to models for the total sales based on discrete choice models.Key words and phrases. MCI model, discrete choice model, market-shares, price elasitcity, regression model....

Design and utilisation of protocols to characterise dynamic PET uptake of two tracers using basis pursuit

Science.gov (United States)

Bell, Christopher; Puttick, Simon; Rose, Stephen; Smith, Jye; Thomas, Paul; Dowson, Nicholas

2017-06-01

Imaging using more than one biological process using PET could be of great utility, but despite previously proposed approaches to dual-tracer imaging, it is seldom performed. The alternative of performing multiple scans is often infeasible for clinical practice or even in research studies. Dual-tracer PET scanning allows for multiple PET radiotracers to be imaged within the same imaging session. In this paper we describe our approach to utilise the basis pursuit method to aid in the design of dual-tracer PET imaging experiments, and later in separation of the signals. The advantage of this approach is that it does not require a compartment model architecture to be specified or even that both signals are distinguishable in all cases. This means the method for separating dual-tracer signals can be used for many feasible and useful combinations of biology or radiotracer, once an appropriate scanning protocol has been decided upon. Following a demonstration in separating the signals from two consecutively injected radionuclides in a controlled experiment, phantom and list-mode mouse experiments demonstrated the ability to test the feasibility of dual-tracer imaging protocols for multiple injection delays. Increases in variances predicted for kinetic macro-parameters V D and K I in brain and tumoral tissue were obtained when separating the synthetically combined data. These experiments confirmed previous work using other approaches that injections delays of 10-20 min ensured increases in variance were kept minimal for the test tracers used. On this basis, an actual dual-tracer experiment using a 20 min delay was performed using these radio tracers, with the kinetic parameters (V D and K I) extracted for each tracer in agreement with the literature. This study supports previous work that dual-tracer PET imaging can be accomplished provided certain constraints are adhered to. The utilisation of basis pursuit techniques, with its removed need to specify a model

Immunohistochemical Analysis of Collagen IV and Laminin Expression in Spontaneous Melanoma Regression in the Melanoma-Bearing Libechov Minipig

Czech Academy of Sciences Publication Activity Database

Plánská, Daniela; Burocziová, Monika; Strnádel, Ján; Horák, Vratislav

2015-01-01

Roč. 48, č. 1 (2015), s. 15-26 ISSN 0044-5991 R&D Projects: GA MŠk ED2.1.00/03.0124 Institutional support: RVO:67985904 ; RVO:61388971 Keywords : collagen IV * laminin * MeLiM * porcine melanoma * spontaneous regression Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 0.912, year: 2015

Stochastic search, optimization and regression with energy applications

Science.gov (United States)

Hannah, Lauren A.

Designing clean energy systems will be an important task over the next few decades. One of the major roadblocks is a lack of mathematical tools to economically evaluate those energy systems. However, solutions to these mathematical problems are also of interest to the operations research and statistical communities in general. This thesis studies three problems that are of interest to the energy community itself or provide support for solution methods: R&D portfolio optimization, nonparametric regression and stochastic search with an observable state variable. First, we consider the one stage R&D portfolio optimization problem to avoid the sequential decision process associated with the multi-stage. The one stage problem is still difficult because of a non-convex, combinatorial decision space and a non-convex objective function. We propose a heuristic solution method that uses marginal project values---which depend on the selected portfolio---to create a linear objective function. In conjunction with the 0-1 decision space, this new problem can be solved as a knapsack linear program. This method scales well to large decision spaces. We also propose an alternate, provably convergent algorithm that does not exploit problem structure. These methods are compared on a solid oxide fuel cell R&D portfolio problem. Next, we propose Dirichlet Process mixtures of Generalized Linear Models (DPGLM), a new method of nonparametric regression that accommodates continuous and categorical inputs, and responses that can be modeled by a generalized linear model. We prove conditions for the asymptotic unbiasedness of the DP-GLM regression mean function estimate. We also give examples for when those conditions hold, including models for compactly supported continuous distributions and a model with continuous covariates and categorical response. We empirically analyze the properties of the DP-GLM and why it provides better results than existing Dirichlet process mixture regression

Face Hallucination with Linear Regression Model in Semi-Orthogonal Multilinear PCA Method

Science.gov (United States)

Asavaskulkiet, Krissada

2018-04-01

In this paper, we propose a new face hallucination technique, face images reconstruction in HSV color space with a semi-orthogonal multilinear principal component analysis method. This novel hallucination technique can perform directly from tensors via tensor-to-vector projection by imposing the orthogonality constraint in only one mode. In our experiments, we use facial images from FERET database to test our hallucination approach which is demonstrated by extensive experiments with high-quality hallucinated color faces. The experimental results assure clearly demonstrated that we can generate photorealistic color face images by using the SO-MPCA subspace with a linear regression model.

Detection of epistatic effects with logic regression and a classical linear regression model.

Science.gov (United States)

Malina, Magdalena; Ickstadt, Katja; Schwender, Holger; Posch, Martin; Bogdan, Małgorzata

2014-02-01

To locate multiple interacting quantitative trait loci (QTL) influencing a trait of interest within experimental populations, usually methods as the Cockerham's model are applied. Within this framework, interactions are understood as the part of the joined effect of several genes which cannot be explained as the sum of their additive effects. However, if a change in the phenotype (as disease) is caused by Boolean combinations of genotypes of several QTLs, this Cockerham's approach is often not capable to identify them properly. To detect such interactions more efficiently, we propose a logic regression framework. Even though with the logic regression approach a larger number of models has to be considered (requiring more stringent multiple testing correction) the efficient representation of higher order logic interactions in logic regression models leads to a significant increase of power to detect such interactions as compared to a Cockerham's approach. The increase in power is demonstrated analytically for a simple two-way interaction model and illustrated in more complex settings with simulation study and real data analysis.

Poisson Mixture Regression Models for Heart Disease Prediction.

Science.gov (United States)

Mufudza, Chipo; Erol, Hamza

2016-01-01

Early heart disease control can be achieved by high disease prediction and diagnosis efficiency. This paper focuses on the use of model based clustering techniques to predict and diagnose heart disease via Poisson mixture regression models. Analysis and application of Poisson mixture regression models is here addressed under two different classes: standard and concomitant variable mixture regression models. Results show that a two-component concomitant variable Poisson mixture regression model predicts heart disease better than both the standard Poisson mixture regression model and the ordinary general linear Poisson regression model due to its low Bayesian Information Criteria value. Furthermore, a Zero Inflated Poisson Mixture Regression model turned out to be the best model for heart prediction over all models as it both clusters individuals into high or low risk category and predicts rate to heart disease componentwise given clusters available. It is deduced that heart disease prediction can be effectively done by identifying the major risks componentwise using Poisson mixture regression model.

Poisson Mixture Regression Models for Heart Disease Prediction

Science.gov (United States)

Erol, Hamza

2016-01-01

Early heart disease control can be achieved by high disease prediction and diagnosis efficiency. This paper focuses on the use of model based clustering techniques to predict and diagnose heart disease via Poisson mixture regression models. Analysis and application of Poisson mixture regression models is here addressed under two different classes: standard and concomitant variable mixture regression models. Results show that a two-component concomitant variable Poisson mixture regression model predicts heart disease better than both the standard Poisson mixture regression model and the ordinary general linear Poisson regression model due to its low Bayesian Information Criteria value. Furthermore, a Zero Inflated Poisson Mixture Regression model turned out to be the best model for heart prediction over all models as it both clusters individuals into high or low risk category and predicts rate to heart disease componentwise given clusters available. It is deduced that heart disease prediction can be effectively done by identifying the major risks componentwise using Poisson mixture regression model. PMID:27999611

Regression analysis using dependent Polya trees.

Science.gov (United States)

Schörgendorfer, Angela; Branscum, Adam J

2013-11-30

Many commonly used models for linear regression analysis force overly simplistic shape and scale constraints on the residual structure of data. We propose a semiparametric Bayesian model for regression analysis that produces data-driven inference by using a new type of dependent Polya tree prior to model arbitrary residual distributions that are allowed to evolve across increasing levels of an ordinal covariate (e.g., time, in repeated measurement studies). By modeling residual distributions at consecutive covariate levels or time points using separate, but dependent Polya tree priors, distributional information is pooled while allowing for broad pliability to accommodate many types of changing residual distributions. We can use the proposed dependent residual structure in a wide range of regression settings, including fixed-effects and mixed-effects linear and nonlinear models for cross-sectional, prospective, and repeated measurement data. A simulation study illustrates the flexibility of our novel semiparametric regression model to accurately capture evolving residual distributions. In an application to immune development data on immunoglobulin G antibodies in children, our new model outperforms several contemporary semiparametric regression models based on a predictive model selection criterion. Copyright © 2013 John Wiley & Sons, Ltd.

Revisiting the long memory dynamics of the implied-realized volatility relationship: New evidence from the wavelet regression

Czech Academy of Sciences Publication Activity Database

Baruník, Jozef; Hlínková, M.

2016-01-01

Roč. 54, č. 1 (2016), s. 503-514 ISSN 0264-9993 R&D Projects: GA ČR(CZ) GBP402/12/G097 Institutional support: RVO:67985556 Keywords : wavelet band spectrum regression * corridor implied volatility * realized volatility * fractional cointegration Subject RIV: AH - Economics Impact factor: 1.481, year: 2016 http://library.utia.cas.cz/separaty/2016/E/barunik-0456186.pdf

Applied Regression Modeling A Business Approach

CERN Document Server

Pardoe, Iain

2012-01-01

An applied and concise treatment of statistical regression techniques for business students and professionals who have little or no background in calculusRegression analysis is an invaluable statistical methodology in business settings and is vital to model the relationship between a response variable and one or more predictor variables, as well as the prediction of a response value given values of the predictors. In view of the inherent uncertainty of business processes, such as the volatility of consumer spending and the presence of market uncertainty, business professionals use regression a

Regression of environmental noise in LIGO data

International Nuclear Information System (INIS)

Tiwari, V; Klimenko, S; Mitselmakher, G; Necula, V; Drago, M; Prodi, G; Frolov, V; Yakushin, I; Re, V; Salemi, F; Vedovato, G

2015-01-01

We address the problem of noise regression in the output of gravitational-wave (GW) interferometers, using data from the physical environmental monitors (PEM). The objective of the regression analysis is to predict environmental noise in the GW channel from the PEM measurements. One of the most promising regression methods is based on the construction of Wiener–Kolmogorov (WK) filters. Using this method, the seismic noise cancellation from the LIGO GW channel has already been performed. In the presented approach the WK method has been extended, incorporating banks of Wiener filters in the time–frequency domain, multi-channel analysis and regulation schemes, which greatly enhance the versatility of the regression analysis. Also we present the first results on regression of the bi-coherent noise in the LIGO data. (paper)

An Assessment of risk response strategies practiced in software projects

Directory of Open Access Journals (Sweden)

Vanita Bhoola

2014-11-01

Full Text Available Risk management and success in projects are highly intertwined – better approaches to project risk management tend to increase chances of project success in terms of achieving scope & quality, schedule and cost targets. The process of responding to risk factors during a project’s life cycle is a crucial aspect of risk management referred to as risk response strategies, in this paper. The current research explores the status of risk response strategies applied in the software development projects in India. India provides a young IT-savvy English-speaking population, which is also cost effective. Other than the workforce, the environment for implementation of software projects in India is different from the matured economies. Risk management process is a commonly discussed theme, though its implementation in practice has a huge scope for improvement in India. The paper talks about four fundamental treatments to risk response – Avoidance, Transference, Mitigation and Acceptance (ATMA. From a primary data of 302 project managers, the paper attempts to address the risk response factors that lead to successful achievement of project scope & quality, schedule and cost targets, by using a series of regressions followed with Seemingly Unrelated Regression Equations (SURE modelling. Mitigation emerged as the most significant risk response strategy to achieve project targets. Acceptance, transference, and avoidance of risk were mostly manifested in the forms of transparency in communication across stakeholders, careful study of the nature of risks and close coordination between project team, customers/end-users and top management.

Servant leadership behaviors of aerospace and defense project managers and their relation to project success

Science.gov (United States)

Dominik, Michael T.

The success of a project is dependent in part on the skills, knowledge, and behavior of its leader, the project manager. Despite advances in project manager certifications and professional development, the aerospace and defense industry has continued to see highly visible and expensive project failures partially attributable to failures in leadership. Servant leadership is an emerging leadership theory whose practitioners embrace empowerment, authenticity, humility, accountability, forgiveness, courage, standing back, and stewardship, but has not yet been fully examined in the context of the project manager as leader. The objective of this study was to examine the relationship between servant leadership behaviors demonstrated by aerospace and defense project managers and the resulting success of their projects. Study participants were drawn from aerospace and defense oriented affinity groups from the LinkedInRTM social media web system. The participants rated their project managers using a 30-item servant leadership scale, and rated the success of their project using a 12-item project success scale. One hundred and fifteen valid responses were analyzed from 231 collected samples from persons who had worked for a project manager on an aerospace and defense project within the past year. The results of the study demonstrated statistically significant levels of positive correlation to project success for all eight servant leadership factors independently evaluated. Using multiple linear regression methods, the servant leadership factors of empowerment and authenticity were determined to be substantial and statistically significant predictors of project success. The study results established the potential application of servant leadership as a valid approach for improving outcomes of projects.

Automation of Flight Software Regression Testing

Science.gov (United States)

Tashakkor, Scott B.

2016-01-01

NASA is developing the Space Launch System (SLS) to be a heavy lift launch vehicle supporting human and scientific exploration beyond earth orbit. SLS will have a common core stage, an upper stage, and different permutations of boosters and fairings to perform various crewed or cargo missions. Marshall Space Flight Center (MSFC) is writing the Flight Software (FSW) that will operate the SLS launch vehicle. The FSW is developed in an incremental manner based on "Agile" software techniques. As the FSW is incrementally developed, testing the functionality of the code needs to be performed continually to ensure that the integrity of the software is maintained. Manually testing the functionality on an ever-growing set of requirements and features is not an efficient solution and therefore needs to be done automatically to ensure testing is comprehensive. To support test automation, a framework for a regression test harness has been developed and used on SLS FSW. The test harness provides a modular design approach that can compile or read in the required information specified by the developer of the test. The modularity provides independence between groups of tests and the ability to add and remove tests without disturbing others. This provides the SLS FSW team a time saving feature that is essential to meeting SLS Program technical and programmatic requirements. During development of SLS FSW, this technique has proved to be a useful tool to ensure all requirements have been tested, and that desired functionality is maintained, as changes occur. It also provides a mechanism for developers to check functionality of the code that they have developed. With this system, automation of regression testing is accomplished through a scheduling tool and/or commit hooks. Key advantages of this test harness capability includes execution support for multiple independent test cases, the ability for developers to specify precisely what they are testing and how, the ability to add

Pragmatic Team Compositions in Scrum-Based Development Projects

DEFF Research Database (Denmark)

Ovesen, Nis

2015-01-01

Agile Development techniques have become the industry standard in Software Development in the pursuit for better performance. The popularity of these techniques and methods has caused them to slowly spread to other domains. Thus, the aim of this paper is to identify how some of these Agile Develo...

Forecasting with Dynamic Regression Models

CERN Document Server

Pankratz, Alan

2012-01-01

One of the most widely used tools in statistical forecasting, single equation regression models is examined here. A companion to the author's earlier work, Forecasting with Univariate Box-Jenkins Models: Concepts and Cases, the present text pulls together recent time series ideas and gives special attention to possible intertemporal patterns, distributed lag responses of output to input series and the auto correlation patterns of regression disturbance. It also includes six case studies.

Estimating Loess Plateau Average Annual Precipitation with Multiple Linear Regression Kriging and Geographically Weighted Regression Kriging

Directory of Open Access Journals (Sweden)

Qiutong Jin

2016-06-01

Full Text Available Estimating the spatial distribution of precipitation is an important and challenging task in hydrology, climatology, ecology, and environmental science. In order to generate a highly accurate distribution map of average annual precipitation for the Loess Plateau in China, multiple linear regression Kriging (MLRK and geographically weighted regression Kriging (GWRK methods were employed using precipitation data from the period 1980–2010 from 435 meteorological stations. The predictors in regression Kriging were selected by stepwise regression analysis from many auxiliary environmental factors, such as elevation (DEM, normalized difference vegetation index (NDVI, solar radiation, slope, and aspect. All predictor distribution maps had a 500 m spatial resolution. Validation precipitation data from 130 hydrometeorological stations were used to assess the prediction accuracies of the MLRK and GWRK approaches. Results showed that both prediction maps with a 500 m spatial resolution interpolated by MLRK and GWRK had a high accuracy and captured detailed spatial distribution data; however, MLRK produced a lower prediction error and a higher variance explanation than GWRK, although the differences were small, in contrast to conclusions from similar studies.

The pursuit of longevity - the bringer of peace to the middle East.

Science.gov (United States)

Stambler, Ilia

2014-01-01

Despite the common apprehensions regarding the aging population, this work aims to argue, on both deontological and utilitarian moral grounds, that any increase in general life-expectancy will be beneficial for the Middle East, countering the common fears associated with this increase. A set of ethical arguments concerning increasing longevity is presented, from both the deontological and utilitarian perspective. A wide selection of economic, psychological, demographic and epidemiological literature and databases is analyzed to determine common correlates of extended longevity. On the deontological grounds, the value of extended longevity is derived from the value of life preservation, regardless of its term. On the utilitarian grounds, the value of extended longevity is demonstrated by its correlation with further human values, such as education level and intellectual activity, economic prosperity, equality, solidarity and peacefulness. With the common apprehensions of stagnation and scarcity due to life extension found wanting, the pursuit of longevity by the population can be seen as a cross-cultural and cross-generational good. Though the current study mainly refers to sources and data relevant to the Middle East, a similar pro-longevity argument can be also made for other cultural contexts. In view of its numerous benefits, normatively, the goal of longevity should be set clearly and openly by the society, and actively pursued, or at least discussed, in academia, the political system and broader public.

Cost diviation in road construction projects: The case of Palestine

Directory of Open Access Journals (Sweden)

Ibrahim Mahamid

2012-02-01

Full Text Available This paper investigates the statistical relationship between actual and estimated cost of road construction projects using data from road construction projects awarded in the West Bank in Palestine over the years 2004–2008. The study is based on a sample of 169 road construction projects. Based on this data, regression models are developed. The findings reveal that 100% of projects suffer from cost diverge, it is found that 76% of projects have cost under estimation while 24% have cost over estimation. The discrepancy between estimated and actual cost has an average of 14.6%, ranging from -39% to 98%. The relation between the project size (length and width and the cost diverge is discussed.

Gibrat’s law and quantile regressions

DEFF Research Database (Denmark)

Distante, Roberta; Petrella, Ivan; Santoro, Emiliano

2017-01-01

The nexus between firm growth, size and age in U.S. manufacturing is examined through the lens of quantile regression models. This methodology allows us to overcome serious shortcomings entailed by linear regression models employed by much of the existing literature, unveiling a number of important...

ON REGRESSION REPRESENTATIONS OF STOCHASTIC-PROCESSES

NARCIS (Netherlands)

RUSCHENDORF, L; DEVALK, [No Value

We construct a.s. nonlinear regression representations of general stochastic processes (X(n))n is-an-element-of N. As a consequence we obtain in particular special regression representations of Markov chains and of certain m-dependent sequences. For m-dependent sequences we obtain a constructive

Introduction to the use of regression models in epidemiology.

Science.gov (United States)

Bender, Ralf

2009-01-01

Regression modeling is one of the most important statistical techniques used in analytical epidemiology. By means of regression models the effect of one or several explanatory variables (e.g., exposures, subject characteristics, risk factors) on a response variable such as mortality or cancer can be investigated. From multiple regression models, adjusted effect estimates can be obtained that take the effect of potential confounders into account. Regression methods can be applied in all epidemiologic study designs so that they represent a universal tool for data analysis in epidemiology. Different kinds of regression models have been developed in dependence on the measurement scale of the response variable and the study design. The most important methods are linear regression for continuous outcomes, logistic regression for binary outcomes, Cox regression for time-to-event data, and Poisson regression for frequencies and rates. This chapter provides a nontechnical introduction to these regression models with illustrating examples from cancer research.

Correlates of muscle dysmorphia symptomatology in natural bodybuilders: Distinguishing factors in the pursuit of hyper-muscularity.

Science.gov (United States)

Mitchell, Lachlan; Murray, Stuart B; Hoon, Matthew; Hackett, Daniel; Prvan, Tania; O'Connor, Helen

2017-09-01

Muscle dysmorphia (MD) is characterized by the pathological pursuit of muscularity and leanness, which includes eating- and exercise-related practices. The aim of this cross-sectional study was to identify correlations of MD symptomatology in natural bodybuilders. An online survey assessing diet, supplementation and training practices, and MD and eating disorder symptoms was completed by male bodybuilders with recent experience competing in a drug-tested competition. Sixty participants (age 29.6±7.1 years) completed the survey. Eating disorder scores (β=.298), rate of pre-competition weight loss (β=.307) and number of competitions (β=-.257) were significant predictors of MD. The association between the EAT-26 and MDDI underscores the salience of disordered eating pathology in presentations of MD. Supporting this, greater rate of pre-competition weight loss, which may reflect disordered eating practices, is also associated with MD symptomatology. The inverse association of competition experience suggests novice bodybuilders may display increased MD symptomatology. Copyright © 2017 Elsevier Ltd. All rights reserved.

Perspective: The missing link in academic career planning and development: pursuit of meaningful and aligned work.

Science.gov (United States)

Lieff, Susan J

2009-10-01

Retention of faculty in academic medicine is a growing challenge. It has been suggested that inattention to the humanistic values of the faculty is contributing to this problem. Professional development should consider faculty members' search for meaning, purpose, and professional fulfillment and should support the development of an ability to reflect on these issues. Ensuring the alignment of academic physicians' inner direction with their outer context is critical to professional fulfillment and effectiveness. Personal reflection on the synergy of one's strengths, passions, and values can help faculty members define meaningful work so as to enable clearer career decision making. The premise of this article is that an awareness of and the pursuit of meaningful work and its alignment with the academic context are important considerations in the professional fulfillment and retention of academic faculty. A conceptual framework for understanding meaningful work and alignment and ways in which that framework can be applied and taught in development programs are presented and discussed.

From Rasch scores to regression

DEFF Research Database (Denmark)

Christensen, Karl Bang

2006-01-01

Rasch models provide a framework for measurement and modelling latent variables. Having measured a latent variable in a population a comparison of groups will often be of interest. For this purpose the use of observed raw scores will often be inadequate because these lack interval scale propertie....... This paper compares two approaches to group comparison: linear regression models using estimated person locations as outcome variables and latent regression models based on the distribution of the score....

Producing The New Regressive Left

DEFF Research Database (Denmark)

Crone, Christine

members, this thesis investigates a growing political trend and ideological discourse in the Arab world that I have called The New Regressive Left. On the premise that a media outlet can function as a forum for ideology production, the thesis argues that an analysis of this material can help to trace...... the contexture of The New Regressive Left. If the first part of the thesis lays out the theoretical approach and draws the contextual framework, through an exploration of the surrounding Arab media-and ideoscapes, the second part is an analytical investigation of the discourse that permeates the programmes aired...... becomes clear from the analytical chapters is the emergence of the new cross-ideological alliance of The New Regressive Left. This emerging coalition between Shia Muslims, religious minorities, parts of the Arab Left, secular cultural producers, and the remnants of the political,strategic resistance...

Critical success factors in information technology projects

Directory of Open Access Journals (Sweden)

Ayesha

2017-02-01

Full Text Available The purpose of this study is to determine the critical success factors (CSF of IT projects in Pa-kistan. The identified factors cannot only be functional to exact type IT projects but also to all types of IT projects, their success directly affects the achievement of whole organization. The proposed study of this paper has determined 15 factors influencing the most on the success of IT projects through multiple regression analysis. The survey has disclosed that many CSFs were found related to IT projects but these 15 factors are also the backbone of IT projects. The re-search results obtained clearly indicated that the Leadership Qualities played a significant role in obtaining Top Management support in order to access to resources however, the Leadership Qualities did not play any role on the trained and capable Project Team Members. Besides, it is undoubtedly defined effective communication of the project was established to be influential on the conclusion and contributing factor towards the Success of IT projects in Pakistan. Top Man-agement Support as a whole was not found to play a key role in the IT Project Success.

Mixture of Regression Models with Single-Index

OpenAIRE

Xiang, Sijia; Yao, Weixin

2016-01-01

In this article, we propose a class of semiparametric mixture regression models with single-index. We argue that many recently proposed semiparametric/nonparametric mixture regression models can be considered special cases of the proposed model. However, unlike existing semiparametric mixture regression models, the new pro- posed model can easily incorporate multivariate predictors into the nonparametric components. Backfitting estimates and the corresponding algorithms have been proposed for...

The Difficulty in Following Project Schedule as a Key Project Management Challenge: Family Firm Perspective

Directory of Open Access Journals (Sweden)

Joanna SADKOWSKA

2016-12-01

Full Text Available The problem of how to manage projects successfully has been gaining growing interest for the last decades. The aforementioned is mainly caused by the fact that project management offers a wide range of methods and tools which, when properly used, can stimulate long-term growth of businesses. As a consequence it offers a particular development opportunity for family enterprises which, due to their specificity, have to overcome many difficulties. The primary objective of this paper is to examine whether family enterprises perceive, and to what extent, the factor of following project schedule as a difficulty in the area of project management. 154 Polish family firms representing different sectors were surveyed. The results of regression analysis show that family firms with global range of business activities, on the contrary to those with local or regional ones, do not find the factor of following project schedule as a difficulty. This results manly from the tools employed and the maturity level they have reached in project management. The findings support the current discussion on the specificity and uniqueness of family businesses in relationship to the knowledge area of project management. It also contributes to filling the gap on understanding the functioning of family firms in the emerging economies of Eastern Europe.

Extreme Sparse Multinomial Logistic Regression: A Fast and Robust Framework for Hyperspectral Image Classification

Science.gov (United States)

Cao, Faxian; Yang, Zhijing; Ren, Jinchang; Ling, Wing-Kuen; Zhao, Huimin; Marshall, Stephen

2017-12-01

Although the sparse multinomial logistic regression (SMLR) has provided a useful tool for sparse classification, it suffers from inefficacy in dealing with high dimensional features and manually set initial regressor values. This has significantly constrained its applications for hyperspectral image (HSI) classification. In order to tackle these two drawbacks, an extreme sparse multinomial logistic regression (ESMLR) is proposed for effective classification of HSI. First, the HSI dataset is projected to a new feature space with randomly generated weight and bias. Second, an optimization model is established by the Lagrange multiplier method and the dual principle to automatically determine a good initial regressor for SMLR via minimizing the training error and the regressor value. Furthermore, the extended multi-attribute profiles (EMAPs) are utilized for extracting both the spectral and spatial features. A combinational linear multiple features learning (MFL) method is proposed to further enhance the features extracted by ESMLR and EMAPs. Finally, the logistic regression via the variable splitting and the augmented Lagrangian (LORSAL) is adopted in the proposed framework for reducing the computational time. Experiments are conducted on two well-known HSI datasets, namely the Indian Pines dataset and the Pavia University dataset, which have shown the fast and robust performance of the proposed ESMLR framework.

Do clinical and translational science graduate students understand linear regression? Development and early validation of the REGRESS quiz.

Science.gov (United States)

Enders, Felicity

2013-12-01

Although regression is widely used for reading and publishing in the medical literature, no instruments were previously available to assess students' understanding. The goal of this study was to design and assess such an instrument for graduate students in Clinical and Translational Science and Public Health. A 27-item REsearch on Global Regression Expectations in StatisticS (REGRESS) quiz was developed through an iterative process. Consenting students taking a course on linear regression in a Clinical and Translational Science program completed the quiz pre- and postcourse. Student results were compared to practicing statisticians with a master's or doctoral degree in statistics or a closely related field. Fifty-two students responded precourse, 59 postcourse , and 22 practicing statisticians completed the quiz. The mean (SD) score was 9.3 (4.3) for students precourse and 19.0 (3.5) postcourse (P REGRESS quiz was internally reliable (Cronbach's alpha 0.89). The initial validation is quite promising with statistically significant and meaningful differences across time and study populations. Further work is needed to validate the quiz across multiple institutions. © 2013 Wiley Periodicals, Inc.

The MIDAS Touch: Mixed Data Sampling Regression Models

OpenAIRE

Ghysels, Eric; Santa-Clara, Pedro; Valkanov, Rossen

2004-01-01

We introduce Mixed Data Sampling (henceforth MIDAS) regression models. The regressions involve time series data sampled at different frequencies. Technically speaking MIDAS models specify conditional expectations as a distributed lag of regressors recorded at some higher sampling frequencies. We examine the asymptotic properties of MIDAS regression estimation and compare it with traditional distributed lag models. MIDAS regressions have wide applicability in macroeconomics and �nance.

Suppression Situations in Multiple Linear Regression

Science.gov (United States)

Shieh, Gwowen

2006-01-01

This article proposes alternative expressions for the two most prevailing definitions of suppression without resorting to the standardized regression modeling. The formulation provides a simple basis for the examination of their relationship. For the two-predictor regression, the author demonstrates that the previous results in the literature are…

Significance testing in ridge regression for genetic data

Directory of Open Access Journals (Sweden)

De Iorio Maria

2011-09-01

Full Text Available Abstract Background Technological developments have increased the feasibility of large scale genetic association studies. Densely typed genetic markers are obtained using SNP arrays, next-generation sequencing technologies and imputation. However, SNPs typed using these methods can be highly correlated due to linkage disequilibrium among them, and standard multiple regression techniques fail with these data sets due to their high dimensionality and correlation structure. There has been increasing interest in using penalised regression in the analysis of high dimensional data. Ridge regression is one such penalised regression technique which does not perform variable selection, instead estimating a regression coefficient for each predictor variable. It is therefore desirable to obtain an estimate of the significance of each ridge regression coefficient. Results We develop and evaluate a test of significance for ridge regression coefficients. Using simulation studies, we demonstrate that the performance of the test is comparable to that of a permutation test, with the advantage of a much-reduced computational cost. We introduce the p-value trace, a plot of the negative logarithm of the p-values of ridge regression coefficients with increasing shrinkage parameter, which enables the visualisation of the change in p-value of the regression coefficients with increasing penalisation. We apply the proposed method to a lung cancer case-control data set from EPIC, the European Prospective Investigation into Cancer and Nutrition. Conclusions The proposed test is a useful alternative to a permutation test for the estimation of the significance of ridge regression coefficients, at a much-reduced computational cost. The p-value trace is an informative graphical tool for evaluating the results of a test of significance of ridge regression coefficients as the shrinkage parameter increases, and the proposed test makes its production computationally feasible.

Regression calibration with more surrogates than mismeasured variables

KAUST Repository

Kipnis, Victor

2012-06-29

In a recent paper (Weller EA, Milton DK, Eisen EA, Spiegelman D. Regression calibration for logistic regression with multiple surrogates for one exposure. Journal of Statistical Planning and Inference 2007; 137: 449-461), the authors discussed fitting logistic regression models when a scalar main explanatory variable is measured with error by several surrogates, that is, a situation with more surrogates than variables measured with error. They compared two methods of adjusting for measurement error using a regression calibration approximate model as if it were exact. One is the standard regression calibration approach consisting of substituting an estimated conditional expectation of the true covariate given observed data in the logistic regression. The other is a novel two-stage approach when the logistic regression is fitted to multiple surrogates, and then a linear combination of estimated slopes is formed as the estimate of interest. Applying estimated asymptotic variances for both methods in a single data set with some sensitivity analysis, the authors asserted superiority of their two-stage approach. We investigate this claim in some detail. A troubling aspect of the proposed two-stage method is that, unlike standard regression calibration and a natural form of maximum likelihood, the resulting estimates are not invariant to reparameterization of nuisance parameters in the model. We show, however, that, under the regression calibration approximation, the two-stage method is asymptotically equivalent to a maximum likelihood formulation, and is therefore in theory superior to standard regression calibration. However, our extensive finite-sample simulations in the practically important parameter space where the regression calibration model provides a good approximation failed to uncover such superiority of the two-stage method. We also discuss extensions to different data structures.

Regression calibration with more surrogates than mismeasured variables

KAUST Repository

Kipnis, Victor; Midthune, Douglas; Freedman, Laurence S.; Carroll, Raymond J.

2012-01-01

In a recent paper (Weller EA, Milton DK, Eisen EA, Spiegelman D. Regression calibration for logistic regression with multiple surrogates for one exposure. Journal of Statistical Planning and Inference 2007; 137: 449-461), the authors discussed fitting logistic regression models when a scalar main explanatory variable is measured with error by several surrogates, that is, a situation with more surrogates than variables measured with error. They compared two methods of adjusting for measurement error using a regression calibration approximate model as if it were exact. One is the standard regression calibration approach consisting of substituting an estimated conditional expectation of the true covariate given observed data in the logistic regression. The other is a novel two-stage approach when the logistic regression is fitted to multiple surrogates, and then a linear combination of estimated slopes is formed as the estimate of interest. Applying estimated asymptotic variances for both methods in a single data set with some sensitivity analysis, the authors asserted superiority of their two-stage approach. We investigate this claim in some detail. A troubling aspect of the proposed two-stage method is that, unlike standard regression calibration and a natural form of maximum likelihood, the resulting estimates are not invariant to reparameterization of nuisance parameters in the model. We show, however, that, under the regression calibration approximation, the two-stage method is asymptotically equivalent to a maximum likelihood formulation, and is therefore in theory superior to standard regression calibration. However, our extensive finite-sample simulations in the practically important parameter space where the regression calibration model provides a good approximation failed to uncover such superiority of the two-stage method. We also discuss extensions to different data structures.

Few crystal balls are crystal clear : eyeballing regression

International Nuclear Information System (INIS)

Wittebrood, R.T.

1998-01-01

The theory of regression and statistical analysis as it applies to reservoir analysis was discussed. It was argued that regression lines are not always the final truth. It was suggested that regression lines and eyeballed lines are often equally accurate. The many conditions that must be fulfilled to calculate a proper regression were discussed. Mentioned among these conditions were the distribution of the data, hidden variables, knowledge of how the data was obtained, the need for causal correlation of the variables, and knowledge of the manner in which the regression results are going to be used. 1 tab., 13 figs

Regression methods for medical research

CERN Document Server

Tai, Bee Choo

2013-01-01

Regression Methods for Medical Research provides medical researchers with the skills they need to critically read and interpret research using more advanced statistical methods. The statistical requirements of interpreting and publishing in medical journals, together with rapid changes in science and technology, increasingly demands an understanding of more complex and sophisticated analytic procedures.The text explains the application of statistical models to a wide variety of practical medical investigative studies and clinical trials. Regression methods are used to appropriately answer the

Should metacognition be measured by logistic regression?

Science.gov (United States)

Rausch, Manuel; Zehetleitner, Michael

2017-03-01

Are logistic regression slopes suitable to quantify metacognitive sensitivity, i.e. the efficiency with which subjective reports differentiate between correct and incorrect task responses? We analytically show that logistic regression slopes are independent from rating criteria in one specific model of metacognition, which assumes (i) that rating decisions are based on sensory evidence generated independently of the sensory evidence used for primary task responses and (ii) that the distributions of evidence are logistic. Given a hierarchical model of metacognition, logistic regression slopes depend on rating criteria. According to all considered models, regression slopes depend on the primary task criterion. A reanalysis of previous data revealed that massive numbers of trials are required to distinguish between hierarchical and independent models with tolerable accuracy. It is argued that researchers who wish to use logistic regression as measure of metacognitive sensitivity need to control the primary task criterion and rating criteria. Copyright © 2017 Elsevier Inc. All rights reserved.

Energy, environment and pursuit of happiness; Energy kankyo mondai ningen no kofuku kara kangaeru

Energy Technology Data Exchange (ETDEWEB)

Shingu, H. [Kyoto University, Kyoto (Japan)

1997-05-05

The energy and environment issue was considered from a viewpoint of human happiness. The paper picks up economy, philosophy, energy and humans as organisms, and considered how the principle of the increase by geometrical progression plays an important role in these. That the repetition in phenomena is like the increase by geometrical progression means that changes increase not linearly but exponentially and nonlinearly and bring such large changes as are unimaginable. The increase in entropy, which is caused by a nonlinear increase of the state, is an irreparable change. The problem of the pursuit of happiness also cannot be solved by the linear thought. The energy and environment problem cannot reach the solution in an extension of the linear thought in which humans have overcome poverty and lacks since the past and pursued richness earnestly. Namely, it is necessary for the 21st century to stop thinking of the energy utilization for seeking for much more richness and to try to think the energy issue in the social system where happiness with not too much richness is presupposed. 16 refs., 1 fig., 1 tab.

The importance of assistive technology in the productivity pursuits of young adults with disabilities.

Science.gov (United States)

Ripat, Jacquie D; Woodgate, Roberta L

2017-01-01

Young adults with disabilities often use assistive technology (AT) to address personal needs, engage in communities and pursue educational and vocational goals. Little is known about their personal experiences and challenges of accessing and using AT for productivity-related activities. This study aimed to learn from young adults about their experiences and use of AT in supporting their productivity. Using a qualitative approach, 20 young adult AT users engaged in semi-structured interviews and a photovoice process. Data were analysed inductively. Three primary themes were identified: I Have to Figure it out Myself, With the Right AT, and Relational Aspects of AT Use. Although participants were experienced AT users, they were often left alone to figure out their emerging needs. They relied on AT to participate in productivity pursuits however stigma around AT use in unsupportive work environments were new concerns. Young adults with disabilities draw on their experiences of AT use but may need to develop advocacy skills to ensure their needs are met in productivity-related environments. Employers and supervisors should recognize AT as essential to young adult's engagement with productivity-related activities and have an important role in developing inclusive work environments.

BOX-COX REGRESSION METHOD IN TIME SCALING

Directory of Open Access Journals (Sweden)

ATİLLA GÖKTAŞ

2013-06-01

Full Text Available Box-Cox regression method with λj, for j = 1, 2, ..., k, power transformation can be used when dependent variable and error term of the linear regression model do not satisfy the continuity and normality assumptions. The situation obtaining the smallest mean square error  when optimum power λj, transformation for j = 1, 2, ..., k, of Y has been discussed. Box-Cox regression method is especially appropriate to adjust existence skewness or heteroscedasticity of error terms for a nonlinear functional relationship between dependent and explanatory variables. In this study, the advantage and disadvantage use of Box-Cox regression method have been discussed in differentiation and differantial analysis of time scale concept.

Gaussian Process Regression Model in Spatial Logistic Regression

Science.gov (United States)

Sofro, A.; Oktaviarina, A.

2018-01-01

Spatial analysis has developed very quickly in the last decade. One of the favorite approaches is based on the neighbourhood of the region. Unfortunately, there are some limitations such as difficulty in prediction. Therefore, we offer Gaussian process regression (GPR) to accommodate the issue. In this paper, we will focus on spatial modeling with GPR for binomial data with logit link function. The performance of the model will be investigated. We will discuss the inference of how to estimate the parameters and hyper-parameters and to predict as well. Furthermore, simulation studies will be explained in the last section.

Regression Analysis and the Sociological Imagination

Science.gov (United States)

De Maio, Fernando

2014-01-01

Regression analysis is an important aspect of most introductory statistics courses in sociology but is often presented in contexts divorced from the central concerns that bring students into the discipline. Consequently, we present five lesson ideas that emerge from a regression analysis of income inequality and mortality in the USA and Canada.

Sparse calibration of subsurface flow models using nonlinear orthogonal matching pursuit and an iterative stochastic ensemble method

KAUST Repository

Elsheikh, Ahmed H.

2013-06-01

We introduce a nonlinear orthogonal matching pursuit (NOMP) for sparse calibration of subsurface flow models. Sparse calibration is a challenging problem as the unknowns are both the non-zero components of the solution and their associated weights. NOMP is a greedy algorithm that discovers at each iteration the most correlated basis function with the residual from a large pool of basis functions. The discovered basis (aka support) is augmented across the nonlinear iterations. Once a set of basis functions are selected, the solution is obtained by applying Tikhonov regularization. The proposed algorithm relies on stochastically approximated gradient using an iterative stochastic ensemble method (ISEM). In the current study, the search space is parameterized using an overcomplete dictionary of basis functions built using the K-SVD algorithm. The proposed algorithm is the first ensemble based algorithm that tackels the sparse nonlinear parameter estimation problem. © 2013 Elsevier Ltd.

An Additive-Multiplicative Cox-Aalen Regression Model

DEFF Research Database (Denmark)

Scheike, Thomas H.; Zhang, Mei-Jie

2002-01-01

Aalen model; additive risk model; counting processes; Cox regression; survival analysis; time-varying effects......Aalen model; additive risk model; counting processes; Cox regression; survival analysis; time-varying effects...

Cascade Optimization for Aircraft Engines With Regression and Neural Network Analysis - Approximators

Science.gov (United States)

Patnaik, Surya N.; Guptill, James D.; Hopkins, Dale A.; Lavelle, Thomas M.

2000-01-01

The NASA Engine Performance Program (NEPP) can configure and analyze almost any type of gas turbine engine that can be generated through the interconnection of a set of standard physical components. In addition, the code can optimize engine performance by changing adjustable variables under a set of constraints. However, for engine cycle problems at certain operating points, the NEPP code can encounter difficulties: nonconvergence in the currently implemented Powell's optimization algorithm and deficiencies in the Newton-Raphson solver during engine balancing. A project was undertaken to correct these deficiencies. Nonconvergence was avoided through a cascade optimization strategy, and deficiencies associated with engine balancing were eliminated through neural network and linear regression methods. An approximation-interspersed cascade strategy was used to optimize the engine's operation over its flight envelope. Replacement of Powell's algorithm by the cascade strategy improved the optimization segment of the NEPP code. The performance of the linear regression and neural network methods as alternative engine analyzers was found to be satisfactory. This report considers two examples-a supersonic mixed-flow turbofan engine and a subsonic waverotor-topped engine-to illustrate the results, and it discusses insights gained from the improved version of the NEPP code.

Online Censoring for Large-Scale Regressions with Application to Streaming Big Data.

Science.gov (United States)

Berberidis, Dimitris; Kekatos, Vassilis; Giannakis, Georgios B

2016-08-01

On par with data-intensive applications, the sheer size of modern linear regression problems creates an ever-growing demand for efficient solvers. Fortunately, a significant percentage of the data accrued can be omitted while maintaining a certain quality of statistical inference with an affordable computational budget. This work introduces means of identifying and omitting less informative observations in an online and data-adaptive fashion. Given streaming data, the related maximum-likelihood estimator is sequentially found using first- and second-order stochastic approximation algorithms. These schemes are well suited when data are inherently censored or when the aim is to save communication overhead in decentralized learning setups. In a different operational scenario, the task of joint censoring and estimation is put forth to solve large-scale linear regressions in a centralized setup. Novel online algorithms are developed enjoying simple closed-form updates and provable (non)asymptotic convergence guarantees. To attain desired censoring patterns and levels of dimensionality reduction, thresholding rules are investigated too. Numerical tests on real and synthetic datasets corroborate the efficacy of the proposed data-adaptive methods compared to data-agnostic random projection-based alternatives.

Kepler AutoRegressive Planet Search

Science.gov (United States)

Caceres, Gabriel Antonio; Feigelson, Eric

2016-01-01

The Kepler AutoRegressive Planet Search (KARPS) project uses statistical methodology associated with autoregressive (AR) processes to model Kepler lightcurves in order to improve exoplanet transit detection in systems with high stellar variability. We also introduce a planet-search algorithm to detect transits in time-series residuals after application of the AR models. One of the main obstacles in detecting faint planetary transits is the intrinsic stellar variability of the host star. The variability displayed by many stars may have autoregressive properties, wherein later flux values are correlated with previous ones in some manner. Our analysis procedure consisting of three steps: pre-processing of the data to remove discontinuities, gaps and outliers; AR-type model selection and fitting; and transit signal search of the residuals using a new Transit Comb Filter (TCF) that replaces traditional box-finding algorithms. The analysis procedures of the project are applied to a portion of the publicly available Kepler light curve data for the full 4-year mission duration. Tests of the methods have been made on a subset of Kepler Objects of Interest (KOI) systems, classified both as planetary `candidates' and `false positives' by the Kepler Team, as well as a random sample of unclassified systems. We find that the ARMA-type modeling successfully reduces the stellar variability, by a factor of 10 or more in active stars and by smaller factors in more quiescent stars. A typical quiescent Kepler star has an interquartile range (IQR) of ~10 e-/sec, which may improve slightly after modeling, while those with IQR ranging from 20 to 50 e-/sec, have improvements from 20% up to 70%. High activity stars (IQR exceeding 100) markedly improve. A periodogram based on the TCF is constructed to concentrate the signal of these periodic spikes. When a periodic transit is found, the model is displayed on a standard period-folded averaged light curve. Our findings to date on real

A tiger beetle’s pursuit of prey depends on distance

Science.gov (United States)

Noest, R. M.; Wang, Z. Jane

2017-04-01

Tiger beetles pursue prey by adjusting their heading according to a time-delayed proportional control law that minimizes the error angle (Haselsteiner et al 2014 J. R. Soc. Interface 11 20140216). This control law can be further interpreted in terms of mechanical actuation: to catch prey, tiger beetles exert a sideways force by biasing their tripod gait in proportion to the error angle measured half a stride earlier. The proportional gain was found to be nearly optimal in the sense that it minimizes the time to point directly toward the prey. For a time-delayed linear proportional controller, the optimal gain, k, is inversely proportional to the time delay, τ, and satisfies kτ =1/e . Here we present evidence that tiger beetles adjust their control gain during their pursuit of prey. Our analysis shows two critical distances: one corresponding to the beetle’s final approach to the prey, and the second, less expected, occurring at a distance around 10 cm for a prey size of 4.5 mm. The beetle initiates its chase using a sub-critical gain and increases the gain to the optimal value once the prey is within this critical distance. Insects use a variety of methods to detect distance, often involving different visual cues. Here we examine two such methods: one based on motion parallax and the other based on the prey’s elevation angle. We show that, in order for the motion parallax method to explain the observed data, the beetle needs to correct for the ratio of the prey’s sideways velocity relative to its own. On the other hand, the simpler method based on the elevation angle can detect both the distance and the prey’s size. Moreover we find that the transition distance corresponds to the accuracy required to distinguish small prey from large predators.

ALTERNATE PURSUIT WITH THREE PARTICIPANTS (THE CASE OF POINTWISE MEETING

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Viktor Shiryayev

2016-03-01

Full Text Available The issues connected with alternate pursuit of escapees group are considered in a number of papers. So in papers [1–3] the solution of the problem has been found in the assumption that the next meeting is selected at the initial time (by the program and the players are moving straight. In paper [4] the solution of the task using the approach of R. Isaacs is given. In paper [5] the choice opportunities of the next meeting ( both software and positional are considered. The article deals with a simple differential game on the pursuer plane P and the coalition of two escapees E={E1,E2}.The movement of all the players are assumed as inertialess. The pursuer speed P exceeds the speed of each of the escapees. The targets, physical abilities and the exact location of each other in any moment of the game are known to all players. The price of the coalition (the pursuer P is (minus the total time spent by the pursuer P on the pointwise meeting with E1 and E2. A coincidence of pursuer and escapee location is meant under the meeting. The choice at the initial time of the persecution is supposed as given (software selectable regular meeting. The limit of the security zone of the second escapee has been found. A geometric approach is used in the problem solving. The resulting system of equations is solved numerically by means of computer algebra, in particular through the Wolfram Mathematics. After defining the boundary of the second escapee security zone one can study the game between the pursuer Р and three escapees acting in concord (the first escapee is eliminated from the game.

Plastic Surgery Overseas: How Much Should a Physician Risk in the Pursuit of Higher-Quality Continuity of Care?

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Schweikart, Scott

2018-04-01

In this article I discuss medical tourism, whereby patients go overseas for plastic surgery treatment in order to save money. However, if malpractice occurs abroad, there are several barriers that make it difficult for patients to recover damages. I explain these legal barriers and then discuss the possible causes of action patients can have over their "domestic physician" (their personal physician who might have referred surgery abroad or who gives postoperative follow-up care) and how these causes of action can create avenues of legal recovery not otherwise available. The possible liability of the domestic physician in the context of surgical malpractice abroad creates an ethical tension in the pursuit of higher-quality continuity of care, as the more involved the physician becomes in the process, the more likely he or she will assume liability. © 2018 American Medical Association. All Rights Reserved.

Model-based Quantile Regression for Discrete Data

KAUST Repository

Padellini, Tullia

2018-04-10

Quantile regression is a class of methods voted to the modelling of conditional quantiles. In a Bayesian framework quantile regression has typically been carried out exploiting the Asymmetric Laplace Distribution as a working likelihood. Despite the fact that this leads to a proper posterior for the regression coefficients, the resulting posterior variance is however affected by an unidentifiable parameter, hence any inferential procedure beside point estimation is unreliable. We propose a model-based approach for quantile regression that considers quantiles of the generating distribution directly, and thus allows for a proper uncertainty quantification. We then create a link between quantile regression and generalised linear models by mapping the quantiles to the parameter of the response variable, and we exploit it to fit the model with R-INLA. We extend it also in the case of discrete responses, where there is no 1-to-1 relationship between quantiles and distribution\\'s parameter, by introducing continuous generalisations of the most common discrete variables (Poisson, Binomial and Negative Binomial) to be exploited in the fitting.

riskRegression

DEFF Research Database (Denmark)

Ozenne, Brice; Sørensen, Anne Lyngholm; Scheike, Thomas

2017-01-01

In the presence of competing risks a prediction of the time-dynamic absolute risk of an event can be based on cause-specific Cox regression models for the event and the competing risks (Benichou and Gail, 1990). We present computationally fast and memory optimized C++ functions with an R interface......-product we obtain fast access to the baseline hazards (compared to survival::basehaz()) and predictions of survival probabilities, their confidence intervals and confidence bands. Confidence intervals and confidence bands are based on point-wise asymptotic expansions of the corresponding statistical...

Influence of Intelletual Stimulation and Conflict Resolution on Project Implementation: A case of Constituency Development Fund Construction Projects in Public Secondary Schools in Kisumu County, Kenya

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Janet Wagude

2015-11-01

Full Text Available Intellectual stimulation is one of the manifestations of transformational leadership. Intellectual stimulation is the aspect of leadership where the leader encourages teams’ ingenuity, creativity and innovative thinking, urging them to keenly question the status quo in order to make discoveries. The purpose of this study was to explore the Influence of intellectual stimulation and conflict resolution on projects implementation. The objective was to determine the Influence of intellectual stimulation and conflict resolution on projects implementation. The study used Expost facto design. Multifactor leadership Questionnaire, Thomas Kilman Instruments, Interview, and documentary analysis were used as tools for data collection. The probability sampling used was stratified and simple random sampling technique. Data was analyzed both quantitatively and qualitatively. Multiple linear regression analysis was used as tool of analysis to test for significance in the hypothesis. One hypothesis was formulated and subsequently tested in the study in order to establish the influence of conflict resolution thereof, in hypothesis H1,( H0: The strength of the relationship between intellectual stimulation and implementation of CDF construction projects does not depend on conflict resolution., it was concluded that the strength of the relationship between intellectual stimulation and implementation of CDF construction projects depends on conflict resolution(P=0.001˂P=0.05,using multiple linear regression analysis the following results were obtained- F value of 7.788,d.f (2,59 and (P-value 0.00˂P= 0.05 significance level which was statistically significant. It was therefore concluded that there is a regression relationship between intellectual stimulation with conflict resolution and implementation of CDF projects. It is therefore recommended that accredited MLQ coaching is desirable, coaching from the systems’ psychodynamic stance could equip the leader in

Real estate value prediction using multivariate regression models

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Manjula, R.; Jain, Shubham; Srivastava, Sharad; Rajiv Kher, Pranav

2017-11-01

The real estate market is one of the most competitive in terms of pricing and the same tends to vary significantly based on a lot of factors, hence it becomes one of the prime fields to apply the concepts of machine learning to optimize and predict the prices with high accuracy. Therefore in this paper, we present various important features to use while predicting housing prices with good accuracy. We have described regression models, using various features to have lower Residual Sum of Squares error. While using features in a regression model some feature engineering is required for better prediction. Often a set of features (multiple regressions) or polynomial regression (applying a various set of powers in the features) is used for making better model fit. For these models are expected to be susceptible towards over fitting ridge regression is used to reduce it. This paper thus directs to the best application of regression models in addition to other techniques to optimize the result.

Use of safety management practices for improving project performance.

Science.gov (United States)

Cheng, Eddie W L; Kelly, Stephen; Ryan, Neal

2015-01-01

Although site safety has long been a key research topic in the construction field, there is a lack of literature studying safety management practices (SMPs). The current research, therefore, aims to test the effect of SMPs on project performance. An empirical study was conducted in Hong Kong and the data collected were analysed with multiple regression analysis. Results suggest that 3 of the 15 SMPs, which were 'safety committee at project/site level', 'written safety policy', and 'safety training scheme' explained the variance in project performance significantly. Discussion about the impact of these three SMPs on construction was provided. Assuring safe construction should be an integral part of a construction project plan.